Exhaust Pressure Control Valve “A

What does it mean?

This generic powertrain/engine diagnostic code generally applies to diesel engines, including but not limited to certain Ford, Dodge, Mercedes, Nissan, and VW vehicles.

This code may also apply to trucks equipped with diesel engines and dealer-installed exhaust brakes.

A valve is placed in the exhaust stream after the exhaust manifold to generate heat in the form of backpressure in the exhaust. This heat and/or backpressure can be used to assist with cold starts. It can also be used to oppose cylinder pressure from the engine cylinders to the exhaust, thereby slowing the engine and the vehicle with it. This is particularly useful during towing operations.

This code strictly pertains to the exhaust pressure control solenoid output circuit. This code is considered an electrical circuit fault only.

Troubleshooting steps may vary depending on the manufacturer, type of exhaust backpressure control, and the color of the control solenoid wires.

Symptoms

Symptoms of a P0475 engine code may include:

    Malfunction Indicator Light (MIL) illuminated
    Lack of power
    Absence of engine braking
    Longer than normal cold engine warm-up time

Potential Causes

Typically, the causes for this code to set are as follows:

    Short to power in the supply circuit between the exhaust pressure control solenoid and the PCM (Powertrain Control Module)
    Open in the supply circuit between the exhaust pressure control solenoid and the PCM
    Short to ground in the exhaust pressure control solenoid supply circuit
    Faulty exhaust pressure control solenoid
    Possibly a failed PCM (highly unlikely)

Diagnostic and Repair Procedures

A good starting point is always to search for a Technical Service Bulletin (TSB) for your specific vehicle. The vehicle manufacturer may have a PCM flash/reprogramming to address this issue, and it’s worth checking before discovering you’ve taken a long/wrong path.

Next, locate the exhaust pressure control solenoid on your specific vehicle. Once located, visually inspect the connectors and wiring. Look for chafing, rubbing, bare wires, burns, or melted plastic. Separate the connectors and carefully inspect the terminals (the metal parts) inside the connectors. See if they appear corroded, burned, or perhaps greenish compared to the normal metal color you’re used to seeing. You can get electrical contact cleaner at any auto parts store if terminal cleaning is needed. If that’s not possible, find 91% rubbing alcohol and a light plastic-bristled brush to clean them. Then let them air dry, get some dielectric silicone compound (same as used for light bulb sockets and spark plug wires), and apply it where the terminals make contact.

If you have a scan tool, clear the diagnostic codes from memory and see if this code returns. If not, the connections were likely your problem.

If the code returns, we’ll need to test the solenoid and its associated circuits. Typically, there are 2 wires to the exhaust pressure control solenoid. First, disconnect the wiring harness from the exhaust pressure control solenoid. With a digital volt-ohm meter (DVOM), connect one meter lead to one terminal of the solenoid. Connect the remaining meter lead to the other terminal of the solenoid. It should not be open or shorted. Check the resistance specifications for your specific vehicle. If the solenoid is open or shorted (infinite resistance or no resistance/0 ohms), replace the solenoid.

If that’s OK, with a DVOM, check that the exhaust pressure control solenoid supply circuit has 12V (red lead to the solenoid supply circuit, black lead to a good ground). Make sure the ignition is on. If there’s no 12 volts at the solenoid, or if there’s 12 volts when the ignition is off, repair the wiring from the PCM or relay to the solenoid, or possibly a faulty PCM.

If that’s fine, check that the exhaust pressure control solenoid is properly grounded. Connect a test light to the positive 12V battery terminal (red terminal) and touch the other end of the test light to the ground circuit going to the exhaust pressure control solenoid circuit ground. If the test light does not illuminate, that would indicate a circuit problem. If it lights up, wiggle the wiring harness going to each sensor to see if the test light flickers, indicating an intermittent connection.

If all tests have passed so far and you continue to get a P0475 code, it would most likely indicate a failing exhaust pressure control solenoid, although a faulty PCM cannot be ruled out until the solenoid has been replaced.

P0476 Exhaust Pressure Control Valve “A” Range/Performance

Understanding Error Code P0476: Exhaust Backpressure Valve Circuit Malfunction

Introduction

What does the P0476 code mean? (General definition: problem with the incoming signal from the exhaust pressure sensor not matching expected values).
This is a generic powertrain/engine diagnostic code, generally applicable to diesel engines (with examples of brands like Ford, Dodge, Mercedes, Nissan, and VW).
May also apply to diesel trucks equipped with dealer-installed exhaust brakes.
Function of the exhaust backpressure valve:
- Generate heat (backpressure) in the exhaust after the manifold.
- Used to facilitate cold starts.
- Used for engine braking (slowing the vehicle, useful for towing).
The P0476 code specifically concerns an incorrect signal from the exhaust pressure sensor relative to the intake manifold pressure, ambient pressure, or pre-programmed values during normal driving.
The cause can be a mechanical or electrical circuit fault, varying depending on the vehicle manufacturer.
Troubleshooting steps may vary by manufacturer, type of backpressure control, and color coding of the control solenoid wires.

Possible Symptoms of Code P0476

List of associated symptoms:
- Malfunction Indicator Lamp (MIL) illuminated
- Lack of power
- Absence of engine braking
- Cold engine warm-up time longer than normal

Potential Causes of Code P0476

List of possible causes:
- Stuck exhaust backpressure valve
- Turbocharger deflector potentially blocked, damaged, or misadjusted
- Restriction or leak in the exhaust system
- Faulty exhaust gas pressure sensor
- PCM (Powertrain Control Module) failure (highly unlikely)

P0476 Diagnostic and Repair Procedures

Essential preliminary step: Search for a Technical Service Bulletin (TSB) specific to your vehicle (make, model, year). The manufacturer may have a software update (PCM flash/reprogramming) to resolve this issue.
Checking for exhaust leaks:
- Listen carefully for abnormal exhaust noises at the manifolds and pipes.
- Look for the presence of black soot indicating a leak.
- If a leak is found, repair it first.
Inspection of the exhaust pressure sensor, connectors, and wiring:
- Locate the sensor on your vehicle.
- Visually inspect the connectors and wiring for chafing, cuts, bare wires, burns, or melted plastic.
- Separate the connectors and carefully examine the metal terminals inside for corrosion, burning, or abnormal discoloration (greenish).
- Clean the terminals if necessary with electrical contact cleaner. If unavailable, use 91% isopropyl alcohol and a soft-bristled plastic brush.
- Let it air dry, then apply a dielectric silicone compound (like that used for bulb sockets and spark plug wires) where the terminals make contact.
Checking the sensing tube (if equipped):
- If your vehicle is equipped, remove the tube connecting the exhaust backpressure sensor to the exhaust manifold.
- Try to blow through it. An obstruction is a possible cause of the code.
Clearing codes and testing:
- If you have a scan tool, clear the diagnostic codes from the memory and see if the P0476 code returns. If not, the problem was likely related to connections.
Checking turbocharger operation (if applicable):
- If you have a scan tool capable of reading boost pressure (or intake manifold pressure).
- Note the pressure with the ignition on, engine off.
- Start the engine and, under safe driving conditions, briefly accelerate to full throttle (without exceeding 2500-3000 RPM).
- You should observe a pressure change of at least 18 PSI (may vary by manufacturer and vehicle year).
- If boost pressure is insufficient, suspect a faulty/misadjusted/stuck wastegate, an exhaust restriction, or a potentially faulty turbocharger.
Testing the exhaust pressure sensor and its circuits:
- Generally, the sensor has 3 wires.
- Disconnect the harness going to the exhaust pressure sensor.
- 5V Power Supply Test: With a digital voltmeter (DVOM), test the 5V supply circuit going to the sensor (red lead on the 5V supply wire, black lead to a good ground). If you measure 12V instead of 5V, repair the wiring between the PCM and the sensor for a short to 12V, or suspect a faulty PCM.
- Signal Circuit Test: With a DVOM, check the voltage on the sensor’s signal circuit (red lead on the sensor signal wire, black lead to a good ground). If you do not measure 5V or if you measure 12V, repair the wiring between the PCM and the sensor, or suspect a faulty PCM.
- Sensor Ground Test: Verify that the exhaust pressure sensor is properly grounded. Connect a test light to the positive battery terminal (red terminal) and touch the other end of the light to the ground circuit going to the sensor circuit ground. If the light does not illuminate, there is a ground circuit problem. If it illuminates, wiggle the wire harness going to the sensor to see if the light flickers, indicating an intermittent connection.
Conclusion: If all previous tests are successful and the P0476 code persists, the exhaust pressure sensor is very likely faulty. However, a PCM failure cannot be ruled out until the sensor has been replaced.

P0477 Exhaust Pressure Control Valve “A” Low

What does it mean?

This generic powertrain/engine diagnostic code generally applies to diesel engines, including but not limited to certain Ford, Dodge, Mercedes, Nissan, and VW vehicles.

This code may also apply to trucks equipped with diesel engines and dealer-installed exhaust brakes.
A valve is placed in the exhaust stream after the exhaust manifold to generate heat in the form of backpressure in the exhaust. This heat and/or backpressure can be used to assist with cold starts. It may also be used to oppose cylinder pressure from the engine cylinders to the exhaust, thereby slowing the engine and the vehicle with it. This is particularly useful during towing operations.

This code is strictly concerned with the incoming signal from the exhaust pressure sensor that does not match the intake manifold pressure or ambient air pressure during normal driving. It could be a mechanical or electrical circuit fault, depending on the vehicle manufacturer.

Troubleshooting steps may vary by manufacturer, type of exhaust backpressure control, and the color of the control solenoid wires.

Symptoms

Symptoms of a P0477 engine code may include:

Malfunction Indicator Lamp (MIL) illuminated
Lack of power
Absence of engine braking
Longer than normal cold engine warm-up time

Potential Causes

Typically, the causes for this code to set are as follows:

Short to power in the supply circuit between the exhaust pressure control solenoid and the PCM (Powertrain Control Module)
Open in the supply circuit between the exhaust pressure control solenoid and the PCM
Short to ground in the exhaust pressure control solenoid supply circuit
Faulty exhaust pressure control relay
Faulty exhaust pressure control solenoid
Possibly a failed PCM (highly unlikely)

Diagnostic and Repair Procedures

Next, locate the exhaust pressure control solenoid on your specific vehicle. Once located, visually inspect the connectors and wiring. Look for chafing, rubbing, bare wires, burns, or melted plastic. Separate the connectors and carefully inspect the terminals (the metal parts) inside the connectors. See if they appear corroded, burnt, or perhaps greenish compared to the normal metal color you’re used to seeing. You can get electrical contact cleaner at any auto parts store if terminal cleaning is needed. If that’s not possible, find 91% rubbing alcohol and a light plastic-bristled brush to clean them. Then, let them air dry, get some dielectric silicone compound (the same used for light bulb sockets and spark plug wires), and apply it where the terminals make contact.

If you have a scan tool, clear the diagnostic codes from memory and see if this code returns. If not, the connections were likely your problem.

If the code returns, locate the relay that operates the exhaust pressure control solenoid. This relay may also be called an exhaust brake or engine brake relay. Once located, swap it with an identical relay in the relay/fuse box that you know is working. Clear the codes and see if this code returns. If not, the relay was likely your problem.

If that’s okay, with a DVOM, check that the exhaust pressure control solenoid supply circuit has 12V (red lead to the solenoid supply circuit, black lead to a good ground). Make sure the ignition is on. If there is no 12 volts at the solenoid, or if there is 12 volts when the ignition is off, repair the wiring from the PCM or relay to the solenoid, or possibly a faulty PCM.

If that’s okay, check that the exhaust pressure control solenoid is properly grounded. Connect a test light to the positive 12V battery terminal (red terminal) and touch the other end of the test light to the ground circuit going to the exhaust pressure control solenoid circuit ground. If the test light does not illuminate, that would indicate a circuit problem. If it lights up, wiggle the wiring harness going in each direction

Exhaust Pressure Control Valve “A” High

What does it mean?

This generic powertrain/engine diagnostic code typically applies to diesel engines, including but not limited to certain Ford Powerstroke, Dodge Cummins, Mercedes, Nissan, and VW vehicles.

This code may also apply to trucks equipped with diesel engines and dealer-installed exhaust brakes.

A valve is placed in the exhaust stream after the exhaust manifold to generate heat in the form of backpressure in the exhaust. This heat and/or backpressure can be used to assist with cold starts. It can also be used to oppose cylinder pressure from the engine’s cylinders to the exhaust, thereby slowing the engine and the vehicle with it. This is particularly useful during towing operations.

Troubleshooting steps may vary by manufacturer, type of exhaust backpressure control, and the color of the control solenoid wires.

Symptoms

Symptoms of a P0478 engine code may include:

    Malfunction Indicator Lamp (MIL) illuminated
    Lack of power
    Absence of engine braking
    Longer than normal cold engine warm-up time

Potential Causes

Typically, the causes for this code to set are:

    Stuck exhaust backpressure valve
    Restricted exhaust
    Open in the ground circuit to the exhaust pressure sensor
    Open in the signal circuit between the exhaust pressure sensor and the PCM
    Short to voltage in the exhaust pressure sensor signal circuit
    Faulty exhaust pressure sensor – internal short to voltage
    Clogged exhaust pressure sensor sensing tube
    Possibly turbocharger overboost
    Possibly the PCM has failed (highly unlikely)

Diagnostic and Repair Procedures

A good starting point is always to search for a Technical Service Bulletin (TSB) for your specific vehicle. The vehicle manufacturer may have a PCM flash/reprogram to address this issue, and it’s worth checking before discovering you’ve taken a long/wrong path. PCM = Powertrain Control Module.

Next, locate the exhaust pressure sensor on your specific vehicle. Once located, visually inspect the connectors and wiring. Look for chafing, rubbing, bare wires, burns, or melted plastic. Disconnect the connectors and carefully inspect the terminals (the metal parts) inside the connectors. See if they appear corroded, burnt, or perhaps greenish compared to the normal metallic color you’re probably used to seeing. You can get electrical contact cleaner at any auto parts store if terminal cleaning is needed. If that’s not possible, find 91% rubbing alcohol and a light plastic-bristled brush to clean them. Then, let them air dry, get some dielectric silicone compound (same as used for light bulb sockets and spark plug wires), and apply a bit where the terminals make contact.

Additionally, if your vehicle is equipped, remove the sensing tube that connects the exhaust backpressure sensor to the exhaust manifold. Try blowing through it. If it’s blocked, that is also a possible cause of this code.

If you have a scan tool, clear the diagnostic codes from memory and see if this code returns. If it doesn’t, the connections were likely your problem.

If the code returns, you’ll need to check the proper operation of the turbocharger overboost. You’ll need a scan tool capable of reading turbocharger boost pressure. You may need to monitor intake manifold pressure, as that will provide the same information. Note the pressure at Key On, but with the engine off. After that, start the engine, drive the vehicle to a safe speed, then momentarily accelerate the engine to full throttle, ensuring the engine speed does not exceed 2500-3000 RPM. You should note a change of at least 18 PSI, perhaps more depending on the vehicle manufacturer and the vehicle’s model year.

If this test passed, or if you were unable to check the turbocharger overboost, we will need to test the sensor and its associated circuits. Typically, there are 3 wires at the exhaust pressure sensor.

Disconnect the harness going to the exhaust pressure sensor. With a digital voltmeter (DVOM), test the 5V supply circuit going to the sensor to ensure it is powered (red wire to the 5V supply circuit, black wire to a good ground). If there are 12 volts at the sensor when there should be 5 volts, repair the wiring from the PCM to the sensor for a short to 12 volts, or possibly a faulty PCM.

If that’s okay, with a DVOM, check that the exhaust pressure sensor signal circuit is 5V (red wire to the sensor signal circuit, black wire to a good ground). If there is no 5 volts at the sensor, or if you see 12 volts at the sensor, repair the wiring from the PCM to the sensor, or again a faulty PCM.

If that’s OK, check that the exhaust pressure sensor is properly grounded. Connect a test light to the positive 12V battery terminal (red terminal) and touch the other end of the test light to the ground circuit going to the exhaust pressure sensor circuit ground. If the test light does not illuminate, that would indicate a circuit problem. If it lights up, wiggle the wire harness going to the exhaust pressure sensor to see if the test light flickers, indicating an intermittent connection.

If all the previous tests passed and you continue to get a P0478 code, it would most likely indicate a failing exhaust pressure sensor, although a closed exhaust backpressure valve or a faulty PCM cannot be ruled out until the sensor has been replaced.

P0479 Intermittent Exhaust Pressure Control Valve “A

What does it mean?

This generic powertrain/engine diagnostic code generally applies to diesel engines, including but not limited to certain Ford, Dodge, Mercedes, Nissan, and VW vehicles.

This code may also apply to trucks equipped with diesel engines and dealer-installed exhaust brakes.

A valve is placed in the exhaust stream after the exhaust manifold to generate heat in the form of backpressure in the exhaust. This heat and/or backpressure can be used to assist with cold starts. It can also be used to oppose cylinder pressure from the engine’s cylinders to the exhaust, thereby slowing the engine and the vehicle with it. This is particularly useful during towing operations.

Troubleshooting steps may vary by manufacturer, type of exhaust backpressure control, and the color of the control solenoid wires.

Symptoms

Symptoms of a P0479 engine code may include:

    Malfunction Indicator Light (MIL) on
    Lack of power
    Absence of engine braking
    Longer than normal cold engine warm-up time

Potential Causes

Typically, the causes for this code to set are:

    Blockage in the exhaust manifold tube to the pressure sensor
    Exhaust system/air intake/supercharger air leaks
    Intermittent open in the exhaust pressure sensor ground circuit
    Intermittent open in the signal circuit between the exhaust pressure sensor and the PCM (Powertrain Control Module)
    Intermittent short to voltage in the signal circuit to the exhaust pressure sensor
    Exhaust gas pressure sensor
    Possibly turbocharger overboost
    Possibly the PCM has failed (highly unlikely)

Diagnostic and Repair Procedures

A good starting point is always to search for a Technical Service Bulletin (TSB) for your specific vehicle. The vehicle manufacturer may have a PCM flash/reprogram to cover this issue, and it’s worth checking before discovering you’ve taken a long/wrong path. PCM = Powertrain Control Module.

If the tube is clear and free, visually inspect the connectors and wiring. Look for chafing, rubbing, bare wires, burns, or melted plastic. Separate the connectors and carefully inspect the terminals (the metal parts) inside the connectors. See if they look corroded, burnt, or perhaps greenish compared to the normal metal color you’re probably used to seeing. You can get electrical contact cleaner at any auto parts store if terminal cleaning is needed. If that’s not possible, find 91% rubbing alcohol and a light plastic-bristled brush to clean them. Then let them air dry, get some dielectric silicone compound (same as used for light bulb sockets and spark plug wires), and apply it where the terminals make contact.

If you have a scan tool, clear the diagnostic codes from memory and see if this code returns. If not, the connections were likely your problem.

If the code returns, you’ll need to check the proper operation of the turbocharger overboost. You’ll need a scan tool capable of reading the turbocharger boost pressure. You may need to monitor the intake manifold pressure, as this will provide the same information. Note the pressure at Key On, but with the engine off. After that, start the engine, drive the vehicle to a safe speed, then momentarily accelerate the engine to full throttle, ensuring the engine speed does not exceed 2500-3000 RPM. You should note a change of at least 18 PSI, perhaps more depending on the vehicle manufacturer and the vehicle’s model year.

If that’s okay, check that the exhaust pressure sensor is properly grounded. Connect a test light to the positive 12V battery terminal (red terminal) and touch the other end of the test light to the ground circuit going to the exhaust pressure sensor circuit ground. If the test light does not illuminate, that would indicate the circuit problem. If it lights up, wiggle the wire harness going to each terminal to see if the test light flickers, indicating an intermittent connection.

If all tests have passed so far and you continue to get a P0479 code, try wiggling the sensor wire harness while watching the scan tool to see if the code returns. If it does, that most likely indicates an intermittent connection in the harness. Otherwise, it would most likely indicate a faulty exhaust pressure sensor, although a closed exhaust pressure control valve or a faulty PCM cannot be ruled out until the sensor has been replaced.

P047A Exhaust Pressure Sensor B Malfunction

What does it mean?

This generic powertrain/engine diagnostic code applies to all engines using variable nozzle turbochargers (gasoline or diesel), starting around 2005 on Ford trucks with 6.0L diesel engines, all Ford EcoBoost engines, and eventually leading to the Cummins 6.7L in 2007, the 3.0L in the Mercedes lineup in 2007, and more recently the Cummins 3.0L 6-cylinder in Nissan vans starting in 2015. This does not necessarily mean you won’t get this code in a VW or other brand.

This code is strictly concerned with the incoming signal from the exhaust pressure sensor not matching the intake manifold pressure or ambient air pressure during power-up. This could be an electrical circuit fault or it could be mechanical.

The P047B code may also be present along with P047A. The only difference between these two codes is the duration of the issue and the type of electrical/mechanical problem encountered by the sensor/circuit/engine controller. Troubleshooting steps may vary by manufacturer, gas or diesel, type of exhaust pressure sensor, and wire colors. Refer to a vehicle-specific repair guide to determine which sensor is “B” for your particular vehicle.

Associated “B” Exhaust Pressure Sensor Fault Codes:

P047B Exhaust Pressure Sensor “B” Circuit Range/Performance
P047C Exhaust Pressure Sensor “B” Circuit Low
P047D Exhaust Pressure Sensor “B” Circuit High
P047E Exhaust Pressure Sensor “B” Circuit Intermittent

Symptoms

Symptoms of a P047A engine code may include:

Check Engine Light on
Lack of power
Unable to perform manual regeneration – burn soot from the particulate filter. It resembles a catalytic converter but has temperature sensors and pressure sensor probes inserted in it.
If it cannot perform regeneration, it may eventually become a no-start condition.

Potential Causes

Typically, the causes for this code to set are:

Blockage in the exhaust manifold tube to the pressure sensor
Exhaust gas recirculation system / air intake / boost air leaks
Exhaust pressure sensor
A Powertrain Control Module (PCM) may be faulty (very unlikely)

Diagnostic and Repair Procedures

Next, locate the exhaust pressure sensor on your specific vehicle. Once located, disconnect the tube connecting the sensor to the exhaust manifold. Try blowing through it. If you can’t, try running a small piece of wire through to dislodge the carbon trapped inside, causing the error code you’re experiencing. If the tube is clear and free, visually inspect the connectors and wiring. Look for chafing, rubbing, bare wires, burns, or melted plastic. Separate the connectors and carefully inspect the terminals (the metal parts) inside the connectors. See if they look corroded, burnt, or perhaps greenish compared to the normal metallic color you’re used to seeing. You can get electrical contact cleaner at any auto parts store if terminal cleaning is needed. If not available, find 91% rubbing alcohol and a soft plastic-bristled brush to clean them. Then let them air dry, get some dielectric silicone compound (same as used for bulb sockets and spark plug wires), and apply a bit where the terminals make contact. Then, ensure the tube connecting the turbocharger to the intake manifold is not leaking. Visually inspect all tube connections around the turbocharger and intake manifold. Tighten all hose/band clamps.

If you have a scan tool, clear the diagnostic codes from memory and see if this code returns. If not, the connections were likely your problem.

If the code returns, we’ll need to test the sensor and its associated circuits. Typically, there are 3 wires to the exhaust pressure sensor.

Disconnect the harness going to the exhaust pressure sensor. With a digital voltmeter (DVOM), test the 5V supply circuit to the sensor to ensure it’s powered (red wire to the 5V supply circuit, black wire to a good ground). If there are 12 volts at the sensor when there should be 5 volts, repair the wiring from the PCM to the sensor for a short to 12 volts, or possibly a faulty PCM.

If that’s okay, with a DVOM, check that the exhaust pressure sensor signal circuit is 5V (red wire to the sensor signal circuit, black wire to a good ground). If there’s no 5 volts at the sensor, or if you see 12 volts at the sensor, repair the wiring from the PCM to the sensor, or again a faulty PCM.

If that’s fine, check that you have an Exhaust Pressure Sensor ground. Connect a test light to the positive 12V battery terminal (red terminal) and touch the other end of the test light to the ground circuit going to the exhaust pressure sensor circuit ground. If the test light does not light up, that would indicate a circuit problem. If it lights up, wiggle the wire harness going to each sensor to see if the test light flickers, indicating an intermittent connection.

If all tests have passed so far and you continue to get a P047A code, that would most likely indicate a failing exhaust pressure sensor, although a faulty PCM cannot be ruled out until the sensor has been replaced.

P047B Exhaust Pressure Sensor B Range / Performance

What does it mean?

The P047A code may also be present at the same time as P047B. The only difference between these two codes is the duration of the issue and the type of electrical/mechanical problem encountered by the sensor/circuit/engine controller. Troubleshooting steps may vary by manufacturer, gas or diesel, type of exhaust pressure sensor, and wire colors. Refer to a vehicle-specific repair guide to determine which sensor is the “B” sensor for your particular vehicle.

A typical exhaust pressure sensor:
Exhaust Pressure Sensor

Associated “B” Exhaust Pressure Sensor Fault Codes:

P047A Exhaust Pressure Sensor “B” Circuit
P047C Exhaust Pressure Sensor “B” Circuit Low Value
P047D Exhaust Pressure Sensor “B” Circuit High
P047E Exhaust Pressure Sensor “B” Circuit Intermittent

Symptoms

Symptoms of a P047B engine code may include:

Check Engine Light on
Lack of power
Unable to perform a manual regeneration – burn soot from the particulate filter. It looks like a catalytic converter but has temperature sensors and pressure sensor probes inserted in it.
If it is unable to perform regeneration, it may eventually result in a no-start condition.

Potential Causes

Typically, the causes for this code to set are:

Diagnostic and Repair Procedures

If the tube is clear and free, visually inspect the connectors and wiring. Look for chafing, rubbing, bare wires, burns, or melted plastic. Separate the connectors and carefully inspect the terminals (the metal parts) inside the connectors. See if they appear corroded, burned, or perhaps greenish compared to the normal metallic color you’re used to seeing. You can get electrical contact cleaner at any auto parts store if terminal cleaning is needed. If that’s not possible, find 91% rubbing alcohol and a light plastic-bristled brush to clean them. Then let them air dry, get some dielectric silicone compound (same as used for bulb sockets and spark plug wires), and apply it where the terminals make contact. Then, ensure the tube connecting the turbocharger to the intake manifold is not leaking. Visually inspect all tube connections around the turbocharger and intake manifold. Tighten all hose/band clamps.

If you have a scan tool, clear the diagnostic codes from memory and see if this code returns. If it doesn’t, the connections were likely your problem.

If the code returns, we’ll need to test the sensor and its associated circuits. Typically, there are 3 wires at the exhaust pressure sensor.

Disconnect the harness going to the exhaust pressure sensor. With a digital voltmeter (DVOM), test the 5V supply circuit going to the sensor to ensure it’s powered (red wire to the 5V supply circuit, black wire to a good ground). If there are 12 volts at the sensor when there should be 5 volts, repair the wiring from the PCM to the sensor for a short to 12 volts, or possibly a faulty PCM.

If that’s okay, check that the exhaust pressure sensor is properly grounded. Connect a test light to the positive 12V battery terminal (red terminal) and touch the other end of the test light to the ground circuit going to the exhaust pressure sensor circuit ground. If the test light does not light up, this would indicate a circuit problem. If it lights up, wiggle the wiring harness going to each sensor to see if the test light flickers, indicating an intermittent connection.

If all tests have passed so far and you continue to get a P047B code, this would most likely indicate a failing exhaust pressure sensor, although a faulty PCM cannot be ruled out until the sensor has been replaced.

P047C Exhaust Pressure Sensor B, Low Input

What does it mean?

This code is strictly concerned with the incoming signal from the exhaust pressure sensor not matching the intake manifold pressure or ambient air pressure during power-up. It is strictly an electrical circuit fault.

The P047B code may also be present along with P047C. The main difference between these two codes is that P047C is solely electrical, while P0471 can result from a mechanical or electrical fault. It is generally recommended to start with P047C (electrical) before moving on to P047B (electrical/mechanical). This way, if the issue is electrical, there’s a higher chance of repair by starting with the electrical system.

Troubleshooting steps may vary by manufacturer, gas or diesel, type of exhaust pressure sensor, and wire colors. Refer to a vehicle-specific repair guide to determine which sensor is “B” for your particular vehicle.

Related “B” exhaust pressure sensor fault codes:

P047A “B” Exhaust Pressure Sensor Circuit
P047B “B” Exhaust Pressure Sensor Circuit Range/Performance
P047D “B” Exhaust Pressure Sensor Circuit High
P047E “B” Exhaust Pressure Sensor Circuit Intermittent

Symptoms

Symptoms of a P047C engine code may include:

Check Engine Light on
Lack of power
Unable to perform a manual regeneration – burn soot from the particulate filter. It resembles a catalytic converter but has temperature sensors and pressure sensor probes inserted in it.
If it cannot perform regeneration, it may eventually result in a no-start condition.

Potential Causes

Typically, the causes for this code to set are:

Open in the signal circuit between the exhaust pressure sensor and the PCM
Open in the power circuit between the exhaust pressure sensor and the PCM
Short to ground in the exhaust pressure sensor signal circuit
Faulty exhaust pressure sensor – internal short to ground
A Powertrain Control Module (PCM) may be faulty (very unlikely)

Diagnostic and Repair Procedures

A good starting point is always to check for a Technical Service Bulletin (TSB) for your specific vehicle. The vehicle manufacturer may have a PCM flash/reprogram to address this issue, and it’s worth checking before discovering you’ve taken a long/wrong path.

Next, locate the exhaust pressure sensor on your specific vehicle. Once located, visually inspect the connectors and wiring. Look for chafing, rubbing, bare wires, burns, or melted plastic. Separate the connectors and carefully inspect the terminals (the metal parts) inside the connectors. See if they appear corroded, burnt, or perhaps greenish compared to the normal metallic color you’re used to seeing. You can get electrical contact cleaner at any auto parts store if terminal cleaning is needed. If that’s not available, find 91% rubbing alcohol and a soft plastic-bristled brush to clean them. Then, let them air dry, get some dielectric silicone compound (the same used for bulb sockets and spark plug wires), and apply it where the terminals make contact.

If you have a scan tool, clear the diagnostic codes from memory and see if this code returns. If not, the connections were likely your issue.

If the code returns, we’ll need to test the sensor and its associated circuits. Typically, there are 3 wires to the exhaust pressure sensor.

Disconnect the harness going to the exhaust pressure sensor. With a digital voltmeter (DVOM), test the 5V power circuit going to the sensor to ensure it’s powered (red wire to the 5V power circuit, black wire to a good ground). If there are 12 volts at the sensor when there should be 5 volts, repair the wiring from the PCM to the sensor for a short to 12 volts, or possibly a faulty PCM.

If all tests have passed so far and you continue to get a P047C code, this would most likely indicate a failing exhaust pressure sensor, although a faulty PCM cannot be ruled out until the sensor has been replaced.

Exhaust Pressure Sensor B, High Input

What does it mean?

This generic powertrain/engine diagnostic code applies to all engines using variable nozzle turbochargers (gasoline or diesel), starting around 2005 on Ford trucks with 6.0L diesel engines, all Ford EcoBoost engines, and eventually leading to the Cummins 6.7L in 2007, the 3.0L in the Mercedes lineup in 2007, and more recently the Cummins 3.0L 6-cylinder in Nissan vans starting in 2015. This does not necessarily mean you won’t get this code in a VW or other brand.

This code is strictly concerned with the incoming signal from the exhaust pressure sensor not matching the intake manifold pressure or ambient air pressure during power-up. It is strictly an electrical circuit fault.

The P047B code may also be present at the same time as P047D. The main difference between these two codes is that P047D is solely electrical, while P047B can be the result of a mechanical or electrical fault. It is generally recommended to start with P047D (electrical) before moving on to P047B (electrical/mechanical). This way, if the problem is electrical, there is a higher likelihood of repair by starting with the electrical system.

Troubleshooting steps may vary depending on the manufacturer, gasoline or diesel, the type of exhaust pressure sensor, and wire colors. Refer to a vehicle-specific repair guide to determine which sensor is the “B” sensor for your particular vehicle.

Related “B” Exhaust Pressure Sensor Fault Codes:

P047A Exhaust Pressure Sensor “B” Circuit
P047B Exhaust Pressure Sensor “B” Circuit Range/Performance
P047C Exhaust Pressure Sensor “B” Circuit Low
P047E Exhaust Pressure Sensor “B” Circuit Intermittent

Symptoms

Symptoms of a P047D engine code may include:

Check Engine Light on
Lack of power
Unable to perform a manual regeneration – burn soot from the particulate filter. It resembles a catalytic converter but has temperature sensors and pressure sensor probes inserted in it.
If it is unable to perform regeneration, it may eventually become a no-start condition.

Potential Causes

Typically, the causes for this code to set are:

Open in the ground circuit to the exhaust pressure sensor
Open in the signal circuit between the exhaust pressure sensor and the PCM
Short to voltage in the exhaust pressure sensor signal circuit
Faulty exhaust pressure sensor – internal short to voltage
A Powertrain Control Module (PCM) may have failed (very unlikely)

Diagnostic and Repair Procedures

A good starting point is always to search for a Technical Service Bulletin (TSB) for your specific vehicle. The vehicle manufacturer may have a PCM flash/reprogram to cover this issue, and it is worth checking before discovering you’ve taken a long/wrong path.

Next, locate the exhaust pressure sensor on your specific vehicle. Once located, visually inspect the connectors and wiring. Look for chafing, rubbing, bare wires, burns, or melted plastic. Separate the connectors and carefully inspect the terminals (the metal parts) inside the connectors. See if they appear corroded, burnt, or perhaps greenish compared to the normal metallic color you are probably used to seeing. You can get electrical contact cleaner at any auto parts store if terminal cleaning is needed. If that’s not possible, find 91% rubbing alcohol and a light plastic-bristled brush to clean them. Then, let them air dry, get some dielectric silicone compound (the same used for light bulb sockets and spark plug wires), and apply it where the terminals make contact.

If you have a scan tool, clear the diagnostic codes from memory and see if this code returns. If it does not, the connections were likely your problem.

If the code returns, we will need to test the sensor and its associated circuits. Typically, there are 3 wires at the exhaust pressure sensor.

Disconnect the harness going to the exhaust pressure sensor. With a digital voltmeter (DVOM), test the 5V supply circuit going to the sensor to ensure it is powered (red wire to the 5V supply circuit, black wire to a good ground). If there are 12 volts at the sensor when there should be 5 volts, repair the wiring from the PCM to the sensor for a short to 12 volts, or possibly a faulty PCM.

If that’s okay, with a DVOM, check that the exhaust pressure sensor signal circuit is 5V (red wire to the sensor signal circuit, black wire to a good ground). If there is no 5 volts at the sensor, or if you see 12 volts at the sensor, repair the wiring from the PCM to the sensor, or again a faulty PCM.

If that is okay, check that the exhaust pressure sensor is properly grounded. Connect a test light to the positive 12V battery terminal (red terminal) and touch the other end of the test light to the ground circuit going to the exhaust pressure sensor circuit ground. If the test light does not illuminate, that would indicate a circuit problem. If it lights up, wiggle the wire harness going to the exhaust pressure sensor to see if the test light flickers, indicating an intermittent connection.

If all tests have passed so far and you continue to get a P047D code, it would most likely indicate a failing exhaust pressure sensor, although a faulty PCM cannot be ruled out until the sensor has been replaced.

P047E Intermittent Exhaust Pressure Sensor Circuit

What does it mean?

This generic powertrain/engine diagnostic code applies to all engines using variable nozzle turbochargers (gasoline or diesel), starting around 2005 on Ford trucks with 6.0L diesel engines, all Ford EcoBoost engines, and eventually leading to the Cummins 6.7L in 2007, the 3.0L in the Mercedes lineup in 2007, and more recently the Cummins 3.0L 6-cylinder in Nissan vans starting in 2015. This does not mean you won’t necessarily get this code in a VW or other brand.

This code is strictly concerned with the incoming signal from the exhaust pressure sensor not matching the intake manifold pressure or ambient air pressure at various times during engine operation. This could be an electrical circuit fault or it could be mechanical.

Codes P047B, P047C, or P047D may also be present along with P047E. The only difference between these codes is the duration of the issue and the type of electrical/mechanical problem encountered by the sensor/circuit/engine controller.

Troubleshooting steps may vary by manufacturer, gas or diesel, type of exhaust pressure sensor, and wire colors. Refer to a vehicle-specific repair guide to determine which sensor is the “B” sensor for your particular vehicle.

Related “B” Exhaust Pressure Sensor Fault Codes:

P047A Exhaust Pressure Sensor “B” Circuit
P047B Exhaust Pressure Sensor “B” Circuit Range/Performance
P047C Exhaust Pressure Sensor “B” Circuit Low Value
P047D Exhaust Pressure Sensor “B” Circuit High

Symptoms

Symptoms of a P047E engine code may include:

Check Engine Light on
Lack of power
Unable to perform a manual regeneration – burn soot from the particulate filter. Looks like a catalytic converter but has temperature sensors and pressure sensor probes inserted into it.
If unable to perform regeneration, it may eventually become a no-start condition.

Potential Causes

Typically, the causes for this code to set are:

Blockage in the exhaust manifold tube to the pressure sensor
Exhaust gas recirculation / air intake / boost air system leaks
Intermittent open in the exhaust pressure sensor ground circuit
Intermittent open in the signal circuit between the exhaust pressure sensor and the PCM
Intermittent short to voltage in the signal circuit to the exhaust pressure sensor
Exhaust gas pressure sensor
A Powertrain Control Module (PCM) may have failed (very unlikely)

Diagnostic and Repair Procedures

A good starting point is always to search for a Technical Service Bulletin (TSB) for your specific vehicle. The vehicle manufacturer may have a PCM flash/reprogramming to cover this issue, and it’s worth checking before finding out you’ve taken a long/wrong path.

Next, locate the exhaust pressure sensor on your specific vehicle. Once located, disconnect the tube connecting the sensor to the exhaust manifold. Try blowing through it. If you can’t, try running a small piece of wire through it to dislodge the carbon trapped inside, causing the error code you’re experiencing.

If the tube is clear and free, visually inspect the connectors and wiring. Look for chafing, rubbing, bare wires, burns, or melted plastic. Separate the connectors and carefully inspect the terminals (the metal parts) inside the connectors. See if they look corroded, burnt, or perhaps greenish compared to the normal metallic color you’re probably used to seeing. You can get electrical contact cleaner at any auto parts store if terminal cleaning is needed. If that’s not possible, find 91% rubbing alcohol and a soft plastic-bristled brush to clean them. Then let them air dry, get some dielectric silicone compound (same as used for light bulb sockets and spark plug wires), and apply a bit where the terminals make contact.

Next, ensure the tube connecting the turbocharger to the intake manifold is not leaking. Visually inspect all tube connections around the turbocharger and intake manifold. Tighten all hose/band clamps.

If you have a scan tool, clear the diagnostic codes from memory and see if this code returns. If it doesn’t, the connections were likely your problem.

If the code returns, we’ll need to test the sensor and its associated circuits. Typically, there are 3 wires to the exhaust pressure sensor. Disconnect the harness going to the exhaust pressure sensor. With a digital voltmeter (DVOM), test the 5V supply circuit going to the sensor to ensure it’s powered (red wire to the 5V supply circuit, black wire to a good ground). If there are 12 volts at the sensor when there should be 5 volts, repair the wiring from the PCM to the sensor for a short to 12 volts, or possibly a faulty PCM.

If that’s OK, with a DVOM, check that you have 5V on the exhaust pressure sensor signal circuit (red wire and sensor signal circuit, black wire to a good ground). If there is no 5 volts at the sensor, or if you see 12 volts at the sensor, repair the wiring from the PCM to the sensor, or again a faulty PCM.

If that’s fine, check that the exhaust pressure sensor is properly grounded. Connect a test light to the positive 12V battery terminal (red terminal) and touch the other end of the test light to the ground circuit going to the exhaust pressure sensor circuit ground. If the test light does not illuminate, that would indicate the circuit problem. If it lights up, wiggle the wire harness going to each terminal to see if the test light flickers, indicating an intermittent connection.

If all tests have passed so far and you continue to get a P047E code, try wiggling the sensor wire harness while watching the scan tool to see if the code returns. If it does, that most likely indicates an intermittent connection in the harness. If not, it would most likely indicate a faulty exhaust pressure sensor, although a faulty PCM cannot be ruled out until the sensor has been replaced.