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.
Exhaust Pressure Sensor B, High Input
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