Symptoms

and severity

The conditions that may trigger this code can also cause internal damage to the engine or fuel system and should be considered urgent. Symptoms of a P2456 code may include:

• Reduced engine performance
• Excessive black smoke from the engine exhaust
• An increase in engine temperatures

Causes

Causes

potential for setting this code are as follows:

• Exhaust leaks
• Open/short circuit(s) in the DPF pressure sensor A circuit
• Faulty DPF pressure sensor
• Clogged, cracked, or collapsed DPF pressure sensor tubes/pipes
• Empty diesel exhaust fluid tank
• Incorrect diesel exhaust fluid

Diagnostic and Repair Procedures

A good starting point is always to check the technical service bulletins (TSBs) for your specific vehicle. Your issue may be a known problem with a known fix released by the manufacturer and can save you time and money when diagnosing.

To properly diagnose a P2456, I need a digital volt/ohmmeter, a manufacturer’s service manual, and a diagnostic scanner.

I would begin my diagnosis with a visual inspection of the related wiring harnesses and connectors. I would inspect the wiring routed near hot exhaust components and/or sharp edges. This saves time if I am certain to check the alternator output, battery voltage, and battery terminal ends at this time.

My next step would be to connect the scanner and retrieve all stored codes and freeze frame data. I would write down this information for future reference and then clear all stored codes.

Using the DVOM, I would follow the manufacturer’s recommendations for testing the DPF pressure sensor. I would consult the service manual for specific instructions. Sensors that do not meet the manufacturer’s resistance specifications should be replaced.

If the sensor checks out, I would continue by checking the DPF pressure sensor supply tubes for obstructions and/or damage. I would replace tubes that are burned, cracked, or collapsed (high-temperature silicone tubes are recommended).

If the supply sensor lines are intact and the sensor is operational, I would proceed by testing the system circuits. To avoid damaging the PCM, I always disconnect the related controllers before testing resistance and/or continuity with the DVOM.

Additional Diagnostic Notes:

• The DPF regeneration fluid must be checked before diagnosing this code
• When P2456 is stored, I have found that clogged sensor ports and clogged sensor tubes are common
• DPF pressure sensor tubes that have melted or been cut may need to be rerouted after replacement

Symptoms

and Severity

Since P2457 is related to the exhaust emission system, it is not considered an urgent code. The symptoms of a P2457 code may include:

• There may be no symptoms when this code is stored
• Reduced fuel efficiency
• A stored code
• Malfunction indicator lamp illumination
• Coolant leak
• Exhaust leak
• Exhaust temperature sensor codes

Causes

Causes

potential causes for setting this code are as follows:

• Low coolant
• Faulty EGR temperature sensor
• Faulty exhaust temperature sensor
• Exhaust leaks
• Clogged EGR cooler
• Engine overheating

Diagnostic and Repair Procedures

A good starting point is always to check the technical service bulletins (TSBs) for your specific vehicle. Your issue may be a known problem with a known fix released by the manufacturer and can save you time and money when diagnosing.

A diagnostic scanner, a digital volt/ohmmeter, a vehicle service manual (or equivalent), and an infrared thermometer with a laser pointer are all tools I would use to diagnose a P2457.

I might start with a visual inspection of the wiring harnesses and connectors associated with the EGR temperature sensor and the exhaust temperature sensor. Carefully examine harnesses that are near hot exhaust pipes and manifolds. Test the battery load, check the battery terminal ends, battery cables, and alternator output before proceeding.

I like to connect the scanner to the vehicle and retrieve all stored codes and freeze frame data at this point. Record the information as you may need it if this turns out to be an intermittent code.

I would observe the scanner data stream to determine if there was actually EGR cooling. Narrow the data stream to include only relevant information for a faster and more accurate data response. If the scanner indicates that the actual temperature inputs are within specifications, suspect a faulty PCM or PCM programming error.

If the EGR temperature sensor data is erratic or does not match the desired parameters, test the sensor following the manufacturer’s recommendations. Replace the sensor if it does not meet the manufacturer’s specifications. If the sensor proves to be in good condition, start testing the EGR temperature sensor circuits. Disconnect all associated controllers before testing with the DVOM. Repair or replace open or shorted circuits as needed.

If the EGR temperature sensor electrical system appears to be functioning normally, use the infrared thermometer to check the exhaust gas temperature at the EGR cooler inlet and at the EGR cooler outlet (with the engine running and at normal operating temperature). Compare your results with the manufacturer’s specifications and replace faulty components if necessary.

Additional Diagnostic Notes:

• Aftermarket mufflers and other exhaust components can cause exhaust temperature variations that could lead to this code being stored
• Exhaust backpressure issues, created by an inadequate diesel particulate filter (DPF), are known to contribute to P2457 storage conditions
• Diagnose and repair DPF-related codes before attempting to diagnose this code
• If the EGR system has been modified using an EGR blocking kit (currently offered by OEMs and aftermarket companies), this type of code may be stored

Severity and Symptoms of Code P2458

The P2458 code indicates a malfunction in the Diesel Particulate Filter (DPF) regeneration system. This issue should be taken seriously, as it can lead to:

⚠️ Increased exhaust backpressure
⚠️ Engine overheating
⚠️ Reduced vehicle performance

Common Symptoms

• 🔥 Excessive black smoke from the exhaust

• 🚗 Difficulty maintaining engine RPM

• 🌡️ Engine or DPF housing overheating

• ⚠️ Other related DPF codes (P2463, P2002, etc.)

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Possible Causes of Code P2458

Several factors can trigger this fault:

🔹 Insufficient diesel exhaust fluid level (AdBlue/DEF)
🔹 Poor quality diesel exhaust fluid
🔹 Wiring issue (short circuit or open circuit)
🔹 DPF pressure sensor failure
🔹 Faulty PCM or programming error
🔹 Clogged pressure sensor pipes

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Diagnosis and Repair of P2458

Step 1: Check Technical Service Bulletins (TSBs)

📌 Consult manufacturer updates – Some DPF issues have official fixes.

Step 2: Electrical System Inspection

🔍 Check wiring harnesses and connectors near the exhaust (risk of overheating and deterioration).
🔋 Test battery voltage and alternator – An unstable power supply can disrupt the system.

Step 3: Code and Data Analysis

📟 Use an OBD-II scanner to retrieve codes and freeze frame data.
🔄 Clear codes and perform a road test – Check if P2458 reappears immediately.

Step 4: Check Diesel Exhaust Fluid (DEF/AdBlue)

✅ Check fluid level and quality (use DEF compliant with ISO 22241).
🔄 Initiate a forced DPF regeneration (if the system allows it).

Step 5: DPF Pressure Sensor Test

📏 Measure sensor resistance with a multimeter (compare to manufacturer specifications).
🚨 Replace the sensor if out of specifications.

Step 6: DPF Pipe Inspection

🧹 Inspect pressure sensor lines – Risk of clogging or sagging.

---

Conclusion

The P2458 code signals a critical problem in the DPF regeneration system. Prompt action is necessary to avoid:

• 🔥 Engine overheating

• ⛽ Increased fuel consumption

• 💰 Costly repairs (DPF replacement)

🔧 Recommended solution: Have the vehicle diagnosed by a professional equipped with a suitable diagnostic tool.

🚗 Experiencing this issue? Share your experience in the comments!

Symptoms and Severity

Since DPF regeneration is essential to maintain the desired exhaust backpressure, addressing a P2459 should be considered a priority. Symptoms of a P2459 code may include:

• Excessive black smoke from the exhaust
• Other DPF codes usually accompany P2459
• Inability to maintain RPM
• Increased engine temperature
• Overheated DPF housing or other exhaust components

The potential causes for setting this code are as follows:

• Faulty DPF pressure sensor
• Faulty exhaust pressure sensor
• Insufficient diesel exhaust fluid
• Incorrect diesel exhaust fluid
• Shorted or open wiring to the DPF injection system
• Faulty PCM or PCM programming error

Diagnostic and Repair Procedures

A good starting point is always to check the technical service bulletins (TSB) for your specific vehicle. Your issue may be a known problem with a known fix published by the manufacturer and can save you time and money during diagnosis.

To diagnose a P2459, a vehicle service manual (or equivalent), a scanner, and a digital volt/ohmmeter will be required.

I like to start by inspecting all cable harnesses and connectors related to the system. I’ve found that this saves me time later, especially if I pay close attention to harnesses located near hot exhaust pipes and manifolds. Now is the time to test the battery load, check battery terminal ends, battery cables, and alternator output.

Now, connect the scanner to the diagnostic port and retrieve all stored fault codes and freeze frame data. Note this information before clearing the codes and testing the vehicle. This can be very helpful later. Test the level and quality of the diesel exhaust fluid and activate the DPF regeneration system if the code does not reset immediately after the road test. If the regeneration procedure was inadvertently interrupted due to another uncorrected issue that has been fixed, the regeneration process can be completed (in the correct increments) at this time.

Follow the manufacturer’s recommendations for testing the DPF pressure sensor (with the DVOM) if the code does not reset immediately. If the sensor does not meet the manufacturer’s resistance specifications, it should be replaced.

Additional Diagnostic Notes:

• Incorrect/insufficient diesel exhaust fluid is a common cause of DPF regeneration sequence/failure frequency codes
• Diagnose and repair DPF pressure sensor codes before attempting to diagnose this code
• Clogged/collapsed DPF pressure sensor hoses/lines are common

How severe is this DTC?

The severity of this code can vary significantly from moderate to severe depending on the specific symptoms of the malfunction and the service level of the cooler and bypass valve. A faulty EGR valve or control circuit can cause excessive ignition and engine pre-ignition that can damage the pistons, valves, and other associated internal engine components.

What are some of the symptoms of the code?

Symptoms of a P245A fault code may include:

• The engine may fail the emissions test
• Ignition ping or knock during acceleration
• Increased fuel consumption
• Poor engine performance
• Service engine soon light illuminated
• Check engine light on

What are some common causes of the code?

Causes

of this P245A code may include:

• Faulty EGR cooler bypass valve
• Clogged or damaged EGR cooler
• Temperature switch malfunction
• Excessive carbon buildup
• Faulty or damaged wiring
• Corroded, damaged, or loose connector
• Faulty ECM

What are the troubleshooting steps for P245A?

The first step in the troubleshooting process for any malfunction is to search for Technical Service Bulletins (TSBs) for the specific vehicle by year, model, and powertrain. In some circumstances, this can save you considerable time in the long run by pointing you in the right direction.

The second step is to locate all components associated with the EGR cooler bypass circuit and check for any potential physical damage. Based on the specific vehicle, this circuit may integrate several components, including the temperature switch, bypass valve, EGR valve, EGR cooler, and ECM. Perform a thorough visual inspection to verify that the associated wiring shows no obvious defects such as scraping, rubbing, bare wires, or burn marks. Then, check the connectors and connections for security, corrosion, and damaged pins. This process must include all wiring connections to all components, including the EGR temperature switch and ECM. Consult vehicle-specific technical data to verify the EGR cooler bypass valve control circuit configuration and confirm each component incorporated into the circuit, which may include a fuse or fusible link in some applications.

Advanced Steps

Advanced steps become very vehicle-specific and require appropriate advanced equipment to perform accurately. These procedures require a digital multimeter and vehicle-specific technical references.

Voltage Checks

Reference voltage and acceptable ranges may vary depending on the specific vehicle and circuit configuration. Specific technical data will include troubleshooting charts and the proper sequence to follow to help you establish an accurate diagnosis.

If this process identifies the absence of a power source or ground, continuity tests may be required to verify the integrity of the wiring, connectors, and other components. Continuity tests should always be performed with the power disconnected from the circuit, and normal readings for wiring and connections should be 0 ohms of resistance. Resistance or lack of continuity is an indication of faulty wiring that is open, shorted, or corroded and must be repaired or replaced.

What are the common repairs for this code?

• Replacement of the EGR cooler
• Replacement of the EGR cooler bypass valve
• Replacement of the temperature switch
• Cleaning corrosion from connectors
• Repairing or replacing faulty wiring
• Cleaning carbon buildup
• ECM replacement

Common Mistake

Replacing the EGR cooler bypass valve when carbon buildup or faulty wiring is causing the ECM to set this code.
I hope the information in this article has been helpful in guiding you in the right direction to correct the issue with the Exhaust Gas Recirculation Cooler Bypass Control Circuit error code. This article is strictly informational, and your vehicle’s specific technical data and service bulletins should always take priority.

How severe is this DTC?

The severity of this code can vary significantly from moderate to severe depending on the specific symptoms of the malfunction and the service level of the cooler and bypass valve. A faulty EGR valve or control circuit can cause engine knocking and pre-ignition that can damage pistons, valves, and other related internal engine components.

What are some of the symptoms of the code?

Symptoms of a P245B trouble code may include:

• The engine may fail the emissions test
• Engine knock or ping during acceleration
• Increased fuel consumption
• Poor engine performance
• Service engine soon light illuminated
• Check engine light on

What are some common causes of the code?

Causes

of this P245B code may include:

• Faulty EGR cooler bypass valve
• Clogged or damaged EGR cooler
• Temperature switch malfunction
• Excessive carbon buildup
• Faulty or damaged wiring
• Corroded, damaged, or loose connector
• Faulty ECM

What are the troubleshooting steps for P245B?

The first step in the troubleshooting process for any malfunction is to research Technical Service Bulletins (TSBs) for the specific vehicle by year, model, and powertrain. In some circumstances, this can save you considerable time in the long run by pointing you in the right direction.

The second step is to locate all components associated with the EGR cooler bypass circuit and look for any potential physical damage. Based on the specific vehicle, this circuit may integrate several components, including the temperature switch, bypass valve, EGR valve, EGR cooler, and ECM. Perform a thorough visual inspection to check that the associated wiring shows no obvious defects such as scraping, rubbing, bare wires, or burn marks. Then, check the connectors and connections for security, corrosion, and damaged pins. This process must include all wiring connections to all components, including the EGR temperature switch and ECM. Consult vehicle-specific technical data to verify the EGR cooler bypass valve control circuit configuration and confirm each component incorporated into the circuit, which may include a fuse or fusible link in some applications.

Advanced Steps

Advanced steps become very vehicle-specific and require appropriate advanced equipment to perform accurately. These procedures require a digital multimeter and vehicle-specific technical references.

Voltage Checks

Reference voltage and acceptable ranges can vary depending on the specific vehicle and circuit configuration. Specific technical data will include troubleshooting charts and the proper sequence to follow to help you establish an accurate diagnosis.

If this process identifies the absence of a power source or ground, continuity tests may be required to verify the integrity of the wiring, connectors, and other components. Continuity tests should always be performed with the power disconnected from the circuit, and normal readings for wiring and connections should be 0 ohms of resistance. Resistance or lack of continuity is an indication of faulty wiring that is open, shorted, or corroded and must be repaired or replaced.

What are the common repairs for this code?

• Replacement of the EGR cooler
• Replacement of the EGR cooler bypass valve
• Replacement of the temperature switch
• Cleaning corrosion from connectors
• Repairing or replacing faulty wiring
• Cleaning carbon buildup
• Replacement of the ECM

Common Mistake

Replacing the EGR cooler bypass valve when carbon buildup or faulty wiring is causing the ECM to set this code.

I hope the information in this article has been helpful in guiding you in the right direction to correct the issue with the Exhaust Gas Recirculation Cooler Bypass Control Circuit error code. This article is strictly informational, and your vehicle’s specific technical data and service bulletins should always take priority.

How severe is this DTC?

The severity of this code can vary significantly from moderate to severe depending on the specific symptoms of the malfunction and the service level of the cooler and bypass valve. A faulty EGR valve or control circuit can cause excessive ignition and engine pre-ignition that can damage the pistons, valves, and other associated internal engine components.

What are some of the symptoms of the code?

Symptoms of a P245C trouble code may include:

• The engine may fail the emissions test
• Ignition ping or knock during acceleration
• Increased fuel consumption
• Poor engine performance
• Service engine soon light illuminated
• Check engine light illuminated

What are some common causes of the code?

Causes

of this P245C code may include:

• Faulty EGR cooler bypass valve
• Clogged or damaged EGR cooler
• Temperature switch malfunction
• Excessive carbon buildup
• Faulty or damaged wiring
• Corroded, damaged, or loose connector
• Faulty ECM

What are the troubleshooting steps for P245C?

The first step in the troubleshooting process for any malfunction is to research the technical service bulletins (TSBs) for the specific vehicle by year, model, and powertrain. In some circumstances, this can save you considerable time in the long run by pointing you in the right direction.

The second step is to locate all components associated with the EGR cooler bypass circuit and check for any potential physical damage. Based on the specific vehicle, this circuit may integrate several components, including the temperature switch, bypass valve, EGR valve, EGR cooler, and ECM. Perform a thorough visual inspection to check the associated wiring for obvious defects such as scraping, rubbing, bare wires, or burns. Then check the connectors and connections for security, corrosion, and damaged pins. This process must include all wiring connections to all components, including the EGR temperature switch and ECM. Consult vehicle-specific technical data to verify the EGR cooler bypass valve control circuit configuration and confirm each component incorporated into the circuit, which may include a fuse or fusible link in some applications.

Advanced Steps

Advanced steps become very vehicle-specific and require appropriate advanced equipment to function accurately. These procedures require a digital multimeter and vehicle-specific technical references.

Voltage Checks

Reference voltage and acceptable ranges may vary depending on the specific vehicle and circuit configuration. Specific technical data will include troubleshooting charts and the proper sequence to follow to help you establish an accurate diagnosis.

If this process identifies the absence of a power source or ground, continuity tests may be required to verify the integrity of the wiring, connectors, and other components. Continuity tests should always be performed with the power disconnected from the circuit, and normal readings for wiring and connections should be 0 ohms of resistance. Resistance or lack of continuity is an indication of faulty wiring that is open, shorted, or corroded and must be repaired or replaced.

What are the common repairs for this code?

• Replacement of the EGR cooler
• Replacement of the EGR cooler bypass valve
• Replacement of the temperature switch
• Cleaning corrosion from connectors
• Repairing or replacing faulty wiring
• Cleaning carbon buildup
• Replacement of the ECM

Common Mistake

Replacing the EGR cooler bypass valve when carbon buildup or faulty wiring is causing the ECM to set this code.
I hope the information in this article has been helpful in guiding you in the right direction to correct the issue with the Exhaust Gas Recirculation Cooler Bypass Control Circuit error code. This article is strictly informational, and your vehicle’s specific technical data and service bulletins should always take priority.

How severe is this DTC?

The severity of this code can vary significantly from moderate to severe depending on the specific symptoms of the malfunction and the service level of the cooler and bypass valve. A faulty EGR valve or control circuit can cause excessive ignition and engine pre-ignition that can damage the pistons, valves, and other associated internal engine components.

What are some of the symptoms of the code?

Symptoms of a P245D trouble code may include:

• The engine may fail the emissions test
• Ignition ping or knock during acceleration
• Increased fuel consumption
• Poor engine performance
• Service engine soon light illuminated
• Check engine light illuminated

What are some common causes of the code?

Causes

of this P245D code may include:

• Faulty EGR cooler bypass valve
• Clogged or damaged EGR cooler
• Temperature switch malfunction
• Excessive carbon buildup
• Faulty or damaged wiring
• Corroded, damaged, or loose connector
• Faulty ECM

What are the troubleshooting steps for P245D?

The first step in the troubleshooting process for any malfunction is to search for Technical Service Bulletins (TSBs) for the specific vehicle by year, model, and powertrain. In some circumstances, this can save you significant time in the long run by pointing you in the right direction.

The second step is to locate all components associated with the EGR cooler bypass circuit and check for any potential physical damage. Based on the specific vehicle, this circuit may integrate several components, including the temperature switch, bypass valve, EGR valve, EGR cooler, and ECM. Perform a thorough visual inspection to check the associated wiring for obvious defects such as scraping, rubbing, bare wires, or burns. Then, check the connectors and connections for security, corrosion, and damaged pins. This process must include all wiring connections to all components, including the EGR temperature switch and ECM. Consult vehicle-specific technical data to verify the EGR cooler bypass valve control circuit configuration and confirm each component incorporated into the circuit, which may include a fuse or fusible link in some applications.

Advanced Steps

Advanced steps become very vehicle-specific and require appropriate advanced equipment to perform accurately. These procedures require a digital multimeter and vehicle-specific technical references.

Voltage Checks

Reference voltage and acceptable ranges may vary depending on the specific vehicle and circuit configuration. Specific technical data will include troubleshooting charts and the proper sequence to follow to help you establish an accurate diagnosis.

If this process identifies the absence of a power source or ground, continuity tests may be required to verify the integrity of the wiring, connectors, and other components. Continuity tests should always be performed with the power disconnected from the circuit, and normal readings for wiring and connections should be 0 ohms of resistance. Resistance or lack of continuity is an indication of faulty wiring that is open, shorted, or corroded and must be repaired or replaced.

What are the common repairs for this code?

• Replacement of the EGR cooler
• Replacement of the EGR cooler bypass valve
• Replacement of the temperature switch
• Cleaning corrosion from connectors
• Repairing or replacing faulty wiring
• Cleaning carbon buildup
• ECM replacement

Common Mistake

Replacing the EGR cooler bypass valve when carbon buildup or faulty wiring is causing the ECM to set this code.
I hope the information contained in this article has been helpful in guiding you in the right direction to correct the issue with the Exhaust Gas Recirculation Cooler Bypass Control Circuit error code. This article is strictly informational, and your vehicle’s specific technical data and service bulletins should always take priority.

Symptoms

and severity

The storage conditions of this code can cause internal damage to the engine or fuel system and must be addressed immediately. Symptoms of a P245E code may include:

• Excessive black smoke from the exhaust
• Decreased engine performance
• Higher engine temperatures
• Higher transmission temperatures

Causes

Potential causes for setting this code are as follows:

• The diesel exhaust fluid tank is empty
• Incorrect diesel exhaust fluid
• Faulty DPF pressure sensor
• Clogged DPF pressure sensor tubes/pipes
• Open or shorted circuit(s) in the DPF pressure sensor B circuit
• Ineffective DPF regeneration
• Malfunctioning active DPF regeneration system

Diagnostic and Repair Procedures

A good starting point is always to check the technical service bulletins (TSBs) for your specific vehicle. Your issue might be a known problem with a published fix from the manufacturer, which can save you time and money during diagnosis.

A diagnostic scanner, a digital volt/ohmmeter, and the manufacturer’s service manual will be needed to diagnose a P245E code. An infrared thermometer may also be helpful.

I usually begin my diagnosis with a visual inspection of the related wiring harnesses and connectors. I would pay close attention to wiring routed near hot exhaust components and sharp edges. Test the battery and battery terminals at this point and check the alternator output.

Next, I would connect the scanner and retrieve all stored codes and freeze frame data. I would write this down for future reference. This can be helpful if the code proves to be intermittent. Now, clear the codes and test-drive the vehicle.

If the code resets immediately, check that the diesel exhaust fluid is present (if applicable) and is the correct type. The most common cause for storing this code is a lack of diesel exhaust fluid. Without the proper type of diesel exhaust fluid, the DPF will not regenerate effectively, potentially causing an increase in exhaust pressure.

Refer to the manufacturer’s service manual for how to test the DPF pressure sensor using the DVOM. If the sensor does not meet the manufacturer’s resistance specifications, it should be replaced. If the sensor appears good, check for any obstructions and/or breaks in the DPF pressure sensor supply pipes. Clean or replace the pipes as needed. High-temperature silicone pipes should be used.

If the sensor is operational and the supply lines are intact, begin testing the system circuits. Disconnect all related control modules before testing resistance and/or continuity with the DVOM. Repair or replace any open or shorted circuits as necessary.

Additional Diagnostic Notes:

• If the DPF pressure sensor hoses are melted or cracked, they may need to be rerouted after replacement
• Consult the owner’s/service manual to determine if your vehicle is equipped with an active or passive DPF regeneration system
• Clogged sensor ports and blocked sensor tubes are common

Symptoms

and severity

This code should be considered urgent, as it indicates conditions that could lead to internal damage to the engine or fuel system. The symptoms of a P245F code may include:

• Decreased engine performance
• Excessive black smoke from the exhaust
• Increased engine temperatures
• Transmission temperatures higher than normal

Causes

Potential causes for this code being set are as follows:

• Clogged DPF pressure sensor tubes/pipes
• Faulty DPF pressure sensor
• The diesel exhaust fluid tank may be empty
• Poor quality diesel exhaust fluid
• Open or shorted circuit(s) in the DPF pressure sensor B circuit
• Ineffective DPF regeneration
• The active DPF regeneration system is inoperative

Diagnostic and Repair Procedures

A good starting point is always to check the technical service bulletins (TSBs) for your specific vehicle. Your issue may be a known problem with a published fix from the manufacturer and can save you time and money during diagnosis.

A manufacturer’s service manual, a diagnostic scanner, and a digital volt/ohmmeter will be essential for diagnosing a P245F code. An infrared thermometer may also be helpful.

I would begin my diagnosis with a visual inspection of the related wiring harnesses and connectors; pay close attention to wiring routed near hot exhaust components and/or sharp edges. Test the alternator output, check the battery and battery terminal ends at this time.

I would continue by connecting the scanner and retrieving all stored codes and freeze frame data. Be sure to note this information for future reference. Clear the codes and test-drive the vehicle.

Check that the diesel exhaust fluid is present (if applicable) and is the correct type, especially if the code resets immediately. A lack of diesel exhaust fluid is likely the most common cause for this code being stored. The DPF will not regenerate effectively without the proper type of diesel exhaust fluid. Poor DPF regeneration will lead to increased exhaust pressure.

Using the DVOM, test the DPF pressure sensor. Consult the manufacturer’s service manual for instructions. The sensor should be replaced if it does not meet the manufacturer’s resistance specifications.

Check for obstructions and/or breaks in the DPF pressure sensor supply pipes, if the sensor checks out. Clean or replace the pipes as needed (high-temperature silicone hoses should be used).

If the supply lines are intact and the sensor is operational, begin testing the system circuits. Disconnect all associated controllers before testing resistance and/or continuity with the DVOM. Repair or replace any open or shorted circuits as necessary.

Additional Diagnostic Notes:

• Clogged sensor ports and clogged sensor tubes are common
• Consult the owner’s/service manual to determine if your vehicle is equipped with an active DPF regeneration system or a passive system
• If the DPF pressure sensor hoses are melted or cracked, they may need to be rerouted after replacement