How severe is this DTC?

A stored P20E6 code should be considered severe and addressed as soon as possible. The SCR system may be disabled because of this. Catalyst damage could occur if the conditions that led to the code being stored are not corrected in a timely manner.

What are some of the symptoms of the code?

Symptoms of a P20E6 fault code may include:

• Reduced fuel efficiency
• Excessive black smoke from the vehicle’s exhaust
• Decreased engine performance
• Other SCR-related codes

What are some common causes of the code?

Causes

of this code may include:

1. Reductant injection air pressure too low
2. Faulty reductant injection air pressure sensor
3. Open or shorted circuits in the reductant injection air pressure sensor system
4. Faulty SCR controller/PCM or programming error

What are the troubleshooting steps for P20E6?

Ensure that the reductant supply/regeneration system is not losing pressure (internally or externally). Activate the pump to create pressure and inspect the system for external leaks. Use a fuel pressure tester to manually monitor the reductant system pressure. Check the supply pump and injector for leaks. If leaks are found (internal or external), they must be repaired before continuing diagnosis.

A diagnostic scanner, digital volt/ohmmeter (DVOM), and vehicle-specific diagnostic information source will be required to diagnose a P20E6 code.

You can use your vehicle information source to locate a technical service bulletin (TSB) that matches the vehicle’s year, make, and model; as well as engine size, stored codes, and presented symptoms. If you find one, it may provide helpful diagnostic information.

Use the scanner (connected to the vehicle’s diagnostic connector) to retrieve all stored codes and relevant freeze frame data. It’s a good idea to note this information before clearing the codes, then test drive the vehicle until the PCM enters readiness mode or the code resets.

If the PCM enters readiness mode at this point, the code is intermittent and may be much more difficult to diagnose. If this is the case, the conditions that led to the code being stored may need to worsen before an accurate diagnosis can be made.

If the code immediately resets, the next step in your diagnosis will require you to search your vehicle information source for diagnostic flowcharts, connector pinout diagrams, connector face views, and component testing procedures/specifications.

Step 1

Use the DVOM to test the reductant injection system pressure sensors according to manufacturer specifications. Components that do not test within allowable parameters should be considered faulty.

Step 2

If reductant injection pressure meets specifications, the P20E6 code persists, and the sensor in question is operational, use the DVOM to test the input and output signal circuits between the sensors and the PCM/SCR controller. Disconnect all controllers before using the DVOM for testing.

Reductant injector sensor codes are often attributed to internally leaking supply pumps

How severe is this DTC?

A stored P20E7 code should be considered severe and addressed as quickly as possible. The SCR system may be disabled because of this. Catalyst damage could occur if the conditions that contributed to the code being stored are not corrected in a timely manner.

What are some of the symptoms of the code?

Symptoms of a P20E7 trouble code may include:

• Reduced fuel efficiency
• Excessive black smoke from the vehicle’s exhaust
• Decreased engine performance
• Other SCR-related codes

What are some common causes of the code?

Causes

of this code may include:

1. Reductant injection air pressure too high
2. Faulty reductant injection air pressure sensor
3. Open or shorted circuits in the reductant injection air pressure sensor system
4. Faulty SCR controller/PCM or programming error

What are the troubleshooting steps for P20E7?

Ensure the reductant supply/regeneration system is not losing pressure (internally or externally). Activate the pump to create pressure and inspect the system for external leaks. Use a fuel pressure tester to manually monitor the reductant system pressure. Check the supply pump and injector for leaks. If leaks are discovered (internal or external), they must be repaired before continuing diagnosis.

A diagnostic scanner, digital volt/ohmmeter (DVOM), and vehicle-specific diagnostic information source will be needed to diagnose a P20E7 code.

You can use your vehicle information source to locate a technical service bulletin (TSB) that matches the vehicle’s year, make, and model; as well as engine size, stored codes, and presented symptoms. If you find one, it might provide helpful diagnostic information.

Use the scanner (connected to the vehicle’s diagnostic connector) to retrieve all stored codes and relevant freeze frame data. It’s a good idea to note this information before clearing the codes, then test drive the vehicle until the PCM enters readiness mode or the code resets.

If the PCM enters readiness mode at this point, the code is intermittent and may be much more difficult to diagnose. If this is the case, the conditions that contributed to the code being stored may need to worsen before an accurate diagnosis can be made.

If the code immediately resets, the next step in your diagnosis will require you to search your vehicle information source for diagnostic flowcharts, connector pinout diagrams, connector face views, and component testing procedures/specifications.

Step 1

Use the DVOM to test the reductant injection system pressure sensors according to manufacturer specifications. Components that do not test within allowable parameters should be considered faulty.

Step 2

If reductant injection pressure is within specifications, the P20E7 code persists, and the sensor in question is operational, use the DVOM to test the input and output signal circuits between the sensors and the PCM/SCR controller. Disconnect all controllers before using the DVOM for testing.

Reductant injector sensor codes are often attributed to internally leaking supply pumps

What does the P20E8 code mean?

The P20E8 code indicates a problem in the system that reduces pollution in diesel engines. This system, called SCR (or DEF/AdBlue), uses a special fluid to reduce harmful emissions.
This error message appears when the reducer fluid pressure is too low, which prevents the system from functioning properly.

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Possible symptoms:

• The engine warning light illuminates on the dashboard

• Possible warning messages related to emissions or AdBlue may appear

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Common causes of the problem:

• DEF pump faulty

• Reducer fluid injector damaged

• Purge valve of the system no longer working correctly

• Hose or pipe of the reducer fluid punctured or clogged

• Pressure sensor faulty

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How to resolve the problem?

1. Visually inspect the cables and connectors related to the DEF system: look for cut wires, broken pins, or signs of corrosion.

2. Check the main components of the system: pump, injector, sensor, valve, and pipes.

3. If in doubt, a diagnosis with an OBD tool can help you precisely locate the fault.

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🔧 Tip: This type of problem can prevent the proper functioning of the anti-pollution system and, eventually, limit the vehicle’s performance or prevent it from starting. Therefore, it is recommended to have the vehicle checked by a professional quickly.

P20E9 Possible Causes

• Damaged reductant pump
• Damaged reductant injector
• Damaged reductant purge valve
• Damaged reductant pressure line
• Damaged reductant pressure sensor

What Does It Mean?

How to Fix P20E9 Code

Check the “possible causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

P20E9 Possible Symptoms

Engine light on (or service engine soon warning light)

P20E9 Meaning

The Powertrain Control Module (PCM) monitors the reductant pressure when the system is preparing for injection. The DEF post-treatment pump has internal diagnostics that assess whether the DEF pump is capable of meeting its demand. If the pump reports insufficient performance for more than a threshold time, the P20E8 code is set.

P20EA Possible Causes

• Faulty reducer control module power relay
• Reducer control module power relay circuit open or shorted
• Poor electrical connection in reducer control module power relay circuit

What Does It Mean?

How to Fix Code P20EA

Check the “possible causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

P20EA Possible Symptoms

Engine light on (or service engine soon warning light)

P20EA Meaning

Reducer control module power relay disabled performance too early is the generic description for code P20EA, but the manufacturer may have a different description.

P20EB Possible Causes

• Defective power relay of the reduction gear control module
• Open or short circuit in the power relay wiring harness of the reduction gear control module
• Poor electrical connection in the power relay circuit of the reduction gear control module

What Does It Mean?

How to Fix Code P20EB

Check the “possible causes” listed above. Visually inspect the related cable harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

P20EB

Possible Symptoms

Engine light on (or service engine soon warning light)

P20EB Meaning

The off-performance of the reduction gear control module power relay is too delayed is the generic description for code P20EB, but the manufacturer may have a different description.

How severe is this DTC?

All stored SCR-related codes can trigger SCR system deactivation. The stored P20EC code should be considered severe and addressed as quickly as possible. Catalyst damage could occur if the code is not corrected promptly.

What are some symptoms of the code?

Symptoms of a P20EC fault code may include:

• Excessive black smoke from vehicle exhaust
• Decreased engine performance
• Reduced fuel efficiency
• Other stored SCR and emission-related codes

What are some common causes of the code?

Causes of this code may include:

1. Faulty exhaust temperature sensor
2. Non-operational SCR system
3. Defective SCR injector
4. Incorrect or insufficient DEF fluid
5. Incorrect SCR controller or programming error
6. Pre-catalyst exhaust leaks
7. Installation of aftermarket or high-performance exhaust components

What are the troubleshooting steps for P20EC?

If other SCR or exhaust emission codes or exhaust temperature codes are stored, these should be addressed before attempting to diagnose the stored P20EC.

All pre-catalyst exhaust leaks must be repaired before attempting diagnosis for this type of code.

Access to a diagnostic scanner, digital volt/ohmmeter (DVOM), infrared thermometer with laser pointer, and vehicle-specific SCR system diagnostic information source will be necessary to diagnose a P20EC code.

Finding a technical service bulletin (TSB) that matches the vehicle’s year, make, and model; as well as engine size, stored codes, and presented symptoms could provide useful diagnostic information.

Begin your diagnosis with a visual inspection of the SCR injection system, exhaust temperature sensors, NOx sensors, and oxygen sensor (O2) harnesses and connectors. Burned or damaged wiring and/or connectors should be repaired or replaced before continuing.

Continue by locating the vehicle’s diagnostic connector and connecting the scanner. Retrieve all stored codes and relevant freeze frame data and record this information before clearing codes. Then test drive the vehicle until the PCM enters readiness mode or the code resets.

If the PCM enters readiness mode, the code is intermittent and may be much more difficult to diagnose at this point. Conditions that contributed to code storage may need to worsen before diagnosis can be achieved.

If the code resets immediately, consult your vehicle information source for diagnostic flowcharts, connector pinout diagrams, connector face views, as well as component testing procedures and specifications. This information will be needed to complete the next steps of your diagnosis.

Observe scanner data flow to compare exhaust temperature sensor data (pre and post catalyst) between engine banks. If inconsistencies are detected, test the exhaust temperature sensors using the DVOM. Sensors that do not meet manufacturer specifications should be considered defective.

If all sensors and circuits appear to be functioning as expected, suspect that the catalyst element is defective or the SCR system has failed.

Ensure the DEF tank is filled with appropriate fluid and has not been contaminated in any way

How severe is this DTC?

All stored SCR-related codes can trigger SCR system deactivation. The stored P20ED code should be considered severe and addressed as quickly as possible. Catalyst damage could occur if the code isn’t corrected promptly.

What are some symptoms of the code?

Symptoms of a P20ED fault code may include:

• Excessive black smoke from vehicle exhaust
• Decreased engine performance
• Reduced fuel efficiency
• Other stored SCR and emission-related codes

What are some common causes of the code?

Causes

of this code may include:

1. Faulty exhaust temperature sensor
2. Malfunctioning SCR system
3. Defective SCR injector
4. Incorrect or insufficient DEF fluid
5. Incorrect SCR controller or programming error
6. Pre-catalyst exhaust leaks
7. Installation of aftermarket or high-performance exhaust components

What are the troubleshooting steps for P20ED?

If other SCR or exhaust emission codes or exhaust temperature codes are stored, these should be addressed before attempting to diagnose the stored P20ED.

All pre-catalyst exhaust leaks must be repaired before attempting diagnosis for this type of code.

Access to a diagnostic scanner, digital volt/ohmmeter (DVOM), infrared thermometer with laser pointer, and vehicle-specific SCR system diagnostic information source will be necessary to diagnose a P20ED code.

Finding a technical service bulletin (TSB) that matches the vehicle’s year, make, and model; along with engine size, stored codes, and presented symptoms could provide useful diagnostic information.

Begin your diagnosis with a visual inspection of the SCR injection system, exhaust temperature sensors, NOx sensors, and oxygen sensor (O2) wiring harnesses and connectors. Burned or damaged wiring and/or connectors should be repaired or replaced before continuing.

Continue by locating the vehicle’s diagnostic connector and connecting the scanner. Retrieve all stored codes and relevant freeze frame data and record this information before clearing codes. Then test drive the vehicle until the PCM enters readiness mode or the code resets.

If the PCM enters readiness mode, the code is intermittent and may be much more difficult to diagnose at this point. Conditions that contributed to code storage may need to worsen before diagnosis can be achieved.

If the code resets immediately, consult your vehicle information source for diagnostic flowcharts, connector pinout diagrams, connector face views, as well as component testing procedures and specifications. This information will be needed to complete the next steps of your diagnosis.

Observe scanner data flow to compare exhaust temperature sensor data (pre and post catalyst) between engine banks. If inconsistencies are detected, test exhaust temperature sensors using the DVOM. Sensors that don’t meet manufacturer specifications should be considered defective.

If all sensors and circuits appear to be functioning as expected, suspect that the catalyst element is defective or the SCR system has failed.

Ensure the DEF tank is filled with the appropriate fluid and hasn’t been contaminated in any way

The P20EE code is associated with a malfunction in the SCR (Selective Catalytic Reduction) system, which is crucial for emission control in modern vehicles. This code must be taken very seriously, as it can lead to severe damage to the catalyst if the issue is not resolved quickly. It is essential to address this code immediately to avoid further damage to the exhaust system and the overall engine performance.

Symptoms Associated with Code P20EE

Symptoms of code P20EE may include the following:

• Excessive black smoke from the exhaust gases.
• Decreased engine performance, including a loss of power.
• Reduced energy efficiency, which may result in increased fuel consumption.
• Other codes related to the SCR system or emissions may also be stored, indicating additional problems.

Common Causes of Code P20EE

Several issues can cause the P20EE code to be recorded. Possible causes include:

• Faulty sensors: Oxygen (O2) sensor, NOx sensor, or exhaust gas temperature sensor.
• Inoperative SCR system: This may be due to a general failure of the SCR system.
• Faulty SCR injector, which prevents proper injection of DEF fluid.
• Insufficient or incorrect DEF fluid level, preventing the SCR system from functioning correctly.
• Problem with the SCR controller or programming error.
• Exhaust leaks before the catalyst, which disrupt the SCR system’s operation.
• Installation of aftermarket or high-performance exhaust parts, which may be incompatible with the vehicle’s SCR system.

How to Repair Code P20EE?

Troubleshooting Steps

1. Checking for other SCR or emission error codes:
   • If other SCR codes or emission-related codes are present, it is important to address them before focusing on P20EE.
2. Repairing exhaust leaks:
   • All exhaust leaks before the catalyst must be repaired. A leak can distort exhaust gas temperature measurements and impair the SCR system’s operation.
3. Using a diagnostic scanner:
   • A diagnostic scanner, a digital voltmeter/ohmmeter (DVOM), and an infrared thermometer will be needed to diagnose and resolve this issue.
   • Consult vehicle-specific diagnostic information, including technical service bulletins (TSBs).
4. Visual inspection:
   • Inspect the SCR injection system, exhaust temperature sensors, NOx sensors, and the wiring/connectors associated with the oxygen sensors. Replace or repair any damaged wires or connectors.
5. Performing tests with the scanner:
   • Connect the diagnostic scanner and retrieve all stored codes, along with relevant data.
   • Test the vehicle until the PCM (Powertrain Control Module) enters readiness mode or the code is reset.
6. Testing sensors:
   • Check the oxygen, NOx, and exhaust gas temperature sensors for any inconsistencies in the scanner data. Use a DVOM to test faulty sensors. If a sensor does not meet the manufacturer’s specifications, it must be replaced.
7. Checking the SCR system:
   • If the sensors and circuits appear to be functioning correctly, but the code persists, there may be an issue with the catalyst element or the SCR system itself.
8. Checking the DEF fluid:
   • Ensure the DEF tank is filled with the appropriate fluid and has not been contaminated.

Conclusion

The P20EE code indicates a critical problem in the SCR system and requires immediate attention to avoid severe damage to the catalyst and vehicle performance. Thorough diagnosis and prompt repair are essential to maintain engine performance and ensure compliance with emission standards.

How severe is this DTC?

All stored SCR-related codes can trigger SCR system deactivation. The stored P20EF code should be considered severe and addressed as quickly as possible. Catalyst damage could occur if the code is not corrected promptly.

What are some symptoms of the code?

Symptoms of a P20EF trouble code may include:

• Excessive black smoke from vehicle exhaust
• Decreased engine performance
• Reduced fuel efficiency
• Other stored SCR and emission-related codes

What are some common causes of the code?

Causes of this code may include:

1. Faulty O2, NOx, or temperature sensor
2. Malfunctioning SCR system
3. Defective SCR injector
4. Incorrect or insufficient DEF fluid
5. Incorrect SCR controller or programming error
6. Pre-catalyst exhaust leaks
7. Installation of aftermarket or high-performance exhaust components

What are the troubleshooting steps for P20EF?

If other SCR or exhaust emission codes or exhaust temperature codes are stored, these should be addressed before attempting to diagnose the stored P20EF.

All pre-catalyst exhaust leaks must be repaired before attempting diagnosis for this type of code.

Access to a diagnostic scanner, digital volt/ohmmeter (DVOM), infrared thermometer with laser pointer, and vehicle-specific SCR system diagnostic information source will be necessary to diagnose a P20EF code.

Finding a technical service bulletin (TSB) that matches the vehicle’s year, make, and model; as well as engine size, stored codes, and presented symptoms could provide useful diagnostic information.

Begin your diagnosis with a visual inspection of the SCR injection system, exhaust temperature sensors, NOx sensors, and oxygen (O2) sensor wiring and connectors. Burned or damaged wiring and/or connectors should be repaired or replaced before continuing.

Continue by locating the vehicle’s diagnostic connector and connecting the scanner. Retrieve all stored codes and relevant freeze frame data and record this information before clearing codes. Then test drive the vehicle until the PCM enters readiness mode or the code resets.

If the PCM enters readiness mode, the code is intermittent and may be much more difficult to diagnose at this point. Conditions that contributed to code storage may need to worsen before diagnosis can be achieved.

If the code resets immediately, consult your vehicle information source for diagnostic flowcharts, connector pinout diagrams, connector face views, as well as component testing procedures and specifications. This information will be needed to complete the next steps of your diagnosis.

Observe scanner data flow to compare O2, NOx, and exhaust gas temperature sensor data (pre and post cat) between engine banks. If inconsistencies are detected, test the respective sensors using the DVOM. Sensors that do not meet manufacturer specifications should be considered faulty.

If all sensors and circuits appear to be functioning as expected, suspect that the catalyst element is defective or the SCR system is malfunctioning.

Ensure the DEF tank is filled with the appropriate fluid and has not been contaminated in any way