How severe is this DTC?

A stored P20C5 code should be considered severe and addressed as quickly as possible. The SCR system could be disabled because of this. Catalyst damage could occur if the conditions that contributed to storing the code are not corrected in a timely manner.

What are some symptoms of the code?

Symptoms of a P20C5 trouble code may include:

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

What are some common causes of the code?

Causes

of this code may include:

• Faulty reductant heater
• Open or shorted circuits in reductant heater control
• Defective reductant temperature sensor
• Faulty SCR controller/PCM or programming error

What are the troubleshooting steps for P20C5?

You will need access to a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a source of vehicle-specific diagnostic information to diagnose a P20C5 code.

If you can find a technical service bulletin (TSB) that matches the vehicle’s year, make, and model; as well as engine size, stored code(s), and presented symptoms, it could provide helpful diagnostic information.

You’ll want to start your diagnosis with a visual inspection of the reductant heater system harnesses and connectors. Burned or damaged wiring and/or connectors should be repaired or replaced before continuing.

Proceed by connecting the scanner to the vehicle’s diagnostic connector and retrieving all stored codes and relevant freeze frame data. Note this information before clearing the codes and test drive the vehicle until the PCM enters readiness mode or the code resets.

The code is intermittent and may be much more difficult to diagnose (for the time being), if the PCM enters readiness mode. If this is the case, the conditions that contributed to storing the code may need to worsen before an accurate diagnosis can be made.

If the code resets, 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 step of your diagnosis.

Use the DVOM to test the SCR/control system power supply. Test fuses with the circuit loaded to avoid misdiagnosis. If proper power (battery voltage) and ground circuits are found, use the scanner to activate the reductant heater(s) and test the output control circuit voltage. If voltage is insufficient, suspect the controller is faulty or encountered a programming error.

If the output voltage circuit is within parameters, use the DVOM to test the reductant heater in question. If the heater does not meet manufacturer specifications, suspect it has failed.

If this code appears in warm weather, suspect a programming error has occurred

How Severe Is This DTC?

A stored P20C6 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 contributed to storing the code are not corrected in a timely manner.

What Are Some of the Symptoms of the Code?

Symptoms of a P20C6 trouble code may include:

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

What Are Some Common Causes of the Code?

Causes of this code may include:

1. Faulty reductant heater
2. Open or shorted circuits in the reductant heater control
3. Defective reductant temperature sensor
4. Faulty SCR controller/PCM or programming error

What Are the P20C6 Troubleshooting Steps?

You will need access to a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a source of vehicle-specific diagnostic information to diagnose a P20C6 code.

If you can find a technical service bulletin (TSB) that matches the vehicle’s year, make, and model, as well as the engine size, stored code(s), and symptoms presented, it may provide helpful diagnostic information.

You will want to start your diagnosis with a visual inspection of the reductant heater system’s wiring harnesses and connectors. Burned or damaged wiring and/or connectors should be repaired or replaced before proceeding.

Proceed by connecting the scanner to the vehicle’s diagnostic connector and retrieving all stored codes and relevant freeze frame data. Note this information before clearing the codes and test drive the vehicle until the PCM enters readiness mode or the code resets.

The code is intermittent and may be much more difficult to diagnose (for the time being) if the PCM enters readiness mode. If this is the case, the conditions that contributed to storing the code may need to worsen before an accurate diagnosis can be made.

If the code resets, 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 step of your diagnosis.

Use the DVOM to test the SCR control system’s power supply. Test fuses with the circuit loaded to avoid misdiagnosis. If the proper power (battery voltage) and ground circuits are found, use the scanner to activate the reductant heater(s) and test the output control circuit voltage. If the voltage is insufficient, suspect a faulty controller or a programming error.

If the output voltage circuit is within parameters, use the DVOM to test the reductant heater in question. If the heater does not meet the manufacturer’s specifications, suspect it has failed.

If this code appears in warm weather, suspect that a programming error has occurred.

How serious is this DTC?

A stored P20C7 code should be considered serious and addressed as soon as possible. The SCR system could 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 P20C7 fault code may include:

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

What are some common causes of the code?

Causes

of this code may include:

• Faulty reductant heater
• Open or shorted circuits in the reductant heater control
• Defective reductant temperature sensor
• Faulty SCR controller/PCM or programming error

What are the troubleshooting steps for P20C7?

You will need access to a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a source of vehicle-specific diagnostic information to diagnose a P20C7 code.

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

You’ll want to start your diagnosis with a visual inspection of the reductant heater system’s wiring harnesses and connectors. Burned or damaged wiring and/or connectors should be repaired or replaced before proceeding.

Proceed by connecting the scanner to the vehicle’s diagnostic connector and retrieving all stored codes and relevant freeze frame data. Note this information before clearing the codes and test drive the vehicle until the PCM enters readiness mode or the code resets.

The code is intermittent and may be much more difficult to diagnose (for the time being) if the PCM enters readiness mode. 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 resets, 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 step of your diagnosis.

Use the DVOM to test the SCR control system’s power supply. Test fuses with the circuit loaded to avoid misdiagnosis. If proper power (battery voltage) and ground circuits are found, use the scanner to activate the reductant heater(s) and test the output control circuit voltage. If the voltage is insufficient, suspect that the controller is faulty or has encountered a programming error.

If the output voltage circuit is within parameters, use the DVOM to test the reductant heater in question. If the heater does not meet the manufacturer’s specifications, suspect that it has failed.

If this code is displayed in warm weather, suspect that a programming error has occurred

How severe is this DTC?

A stored P20C8 code should be considered severe and addressed as quickly as possible. The SCR system could 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 P20C8 trouble code may include:

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

What are some common causes of the code?

Causes

of this code may include:

• Faulty reductant heater
• Open or shorted circuits in the reductant heater control
• Defective reductant temperature sensor
• Faulty SCR controller/PCM or programming error

What are the troubleshooting steps for P20C8?

You will need access to a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a source of vehicle-specific diagnostic information to diagnose a P20C8 code.

If you can find a technical service bulletin (TSB) that matches the vehicle’s year, make, and model; as well as engine size, stored code(s), and presented symptoms, it might provide useful diagnostic information.

You’ll want to start your diagnosis with a visual inspection of the reductant heater system harnesses and connectors. Burned or damaged wiring and/or connectors should be repaired or replaced before continuing.

Proceed by hooking up the scanner to the vehicle’s diagnostic connector and retrieving all stored codes and relevant freeze frame data. Note this information before clearing the codes and test drive the vehicle until the PCM enters readiness mode or the code resets.

The code is intermittent and may be much more difficult to diagnose (for the time being), if the PCM enters readiness mode. 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 resets, 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 step of your diagnosis.

Use the DVOM to test the SCR/control system power supply. Test fuses with the circuit loaded to avoid misdiagnosis. If proper power (battery voltage) and ground circuits are discovered, use the scanner to activate the reductant heater(s) and test the output control circuit voltage. If voltage is insufficient, suspect the controller is faulty or has encountered a programming error.

If the voltage output circuit is within parameters, use the DVOM to test the reductant heater in question. If the heater does not meet manufacturer specifications, suspect it has failed.

If this code is displayed in warm weather, suspect a programming error has occurred

P20C9 Possible Causes

• Faulty Reducer Control Module
• Reducer Control Module Harness is Open or Shorted
• Reducer Control Module Circuit Poor Electrical Connection

What Does It Mean?

How to Fix Code P20C9

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.

P20C9 Possible Symptoms

Engine Light On (or Service Engine Soon Warning Light)

P20C9 Meaning

MIL illumination required for Reducer Control Module is the generic description for code P20C9, but the manufacturer may have a different description

How to Fix Code P20CA

Check the “Possible Causes” listed above. Visually inspect the wiring harness and associated connectors. Check for damaged components and look for connector pins that are broken, bent, pushed out, or corroded.

P20CA

Symptoms

Possible

Check Engine Light illuminated (or Service Engine Soon warning light)

P20CA Meaning

Reductant Air Injection Pressure Leak is the generic description for code P20CA, but the manufacturer may have a different description.

How severe is this DTC?

A stored P20CB code should be considered severe and addressed as soon as possible. The EAS system may be damaged due to the conditions that contributed to storing the P20CB code.

What are some symptoms of the code?

Symptoms of a P20CB fault code may include:

• Decreased engine performance
• Excessive black smoke from vehicle exhaust
• Reduced fuel efficiency
• Other EAS/SCR related codes

What are some common causes of the code?

Causes

of this code may include:

• Faulty EAS fuel injector
• Open or shorted circuits in the EAS fuel injection control circuit
• Insufficient DEF in the EAS tank
• Faulty EAS controller/PCM or programming error

What are the troubleshooting steps for P20CB?

A diagnostic scanner, digital volt/ohmmeter (DVOM), and vehicle-specific diagnostic information source will be needed to diagnose a P20CB 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.

I prefer to start my diagnosis with a visual inspection of EAS wiring harnesses and connectors. Burned or damaged wiring and/or connectors should be repaired or replaced before continuing.

I would continue by plugging the scanner into the vehicle’s diagnostic connector and retrieving all stored codes and relevant freeze frame data. Consider noting this information before clearing codes. 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 storing the code may need to worsen before an accurate diagnosis can be made.

If the code immediately resets, to complete the next step of your diagnosis, you’ll need to consult your vehicle information source for diagnostic flowcharts, connector pinout diagrams, connector face views, as well as component testing procedures and specifications. You can also use your vehicle information source to locate the exact position of the EAS A fuel injector.

Use the DVOM to test (voltage drop) the EAS control system power supply. Test fuses with the circuit loaded to avoid misdiagnosis. If proper power (battery voltage) and ground circuits are confirmed, use the scanner to activate the EAS fuel injector (solenoid) and test the output control circuit voltage. If voltage is insufficient, suspect the controller is faulty or has encountered a programming error.

If the output voltage circuit is within parameters, use the DVOM to test the EAS fuel injector in question. If the injector doesn’t meet manufacturer specifications, suspect it has failed.

The EAS fuel injector is simply a solenoid injector that sprays reducing fluid into the exhaust
Don’t forget ground circuits during voltage drop testing

How severe is this DTC?

A stored P20CC code should be considered severe and addressed as soon as possible. The EAS system may be damaged due to the conditions that contributed to storing the P20CC code.

What are some symptoms of the code?

Symptoms of a P20CC fault code may include:

• Decreased engine performance
• Excessive black smoke from vehicle exhaust
• Reduced fuel efficiency
• Other EAS/SCR related codes

What are some common causes of the code?

Causes

of this code may include:

• Faulty EAS fuel injector
• Open or shorted circuits in the EAS fuel injection control circuit
• Insufficient DEF in the EAS tank
• Faulty EAS controller/PCM or programming error

What are the troubleshooting steps for P20CC?

A diagnostic scanner, digital volt/ohmmeter (DVOM), and vehicle-specific diagnostic information source will be needed to diagnose a P20CC 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 helpful diagnostic information.

I prefer to start my diagnosis with a visual inspection of EAS wiring harnesses and connectors. Burned or damaged wiring and/or connectors should be repaired or replaced before continuing.

I would continue by connecting the scanner to the vehicle’s diagnostic connector and retrieving all stored codes and relevant freeze frame data. Consider noting this information before clearing codes. 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 storing the code may need to worsen before an accurate diagnosis can be made.

If the code immediately resets, to complete the next step of your diagnosis, you’ll need to consult your vehicle information source for diagnostic flowcharts, connector pinout diagrams, connector face views, as well as component testing procedures and specifications. You can also use your vehicle information source to locate the exact position of the EAS A fuel injector.

Use the DVOM to test (voltage drop) the EAS control system power supply. Test fuses with the circuit loaded to avoid misdiagnosis. If proper power (battery voltage) and ground circuits are confirmed, use the scanner to activate the EAS fuel injector (solenoid) and test the output control circuit voltage. If voltage is insufficient, suspect the controller is faulty or encountered a programming error.

If the output voltage circuit is within parameters, use the DVOM to test the EAS fuel injector in question. If the injector doesn’t meet manufacturer specifications, suspect it has failed.

The EAS fuel injector is simply a solenoid injector that sprays reducing fluid into the exhaust
Don’t forget ground circuits during voltage drop testing

How severe is this DTC?

A stored P20CD code should be considered severe and addressed as soon as possible. The EAS system may be damaged due to the conditions that led to the storage of the P20CD code.

What are some of the symptoms of the code?

Symptoms of a P20CD fault code may include:

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

What are some common causes of the code?

Causes

of this code may include:

• Faulty EAS fuel injector
• Open or shorted circuits in the EAS fuel injection control circuit
• Insufficient DEF in the EAS tank
• Faulty EAS controller/PCM or programming error

What are the troubleshooting steps for P20CD?

A diagnostic scanner, digital volt/ohmmeter (DVOM), and vehicle-specific diagnostic information source will be needed to diagnose a P20CD 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.

I prefer to start my diagnosis with a visual inspection of the EAS wiring harnesses and connectors. Burned or damaged wiring and/or connectors should be repaired or replaced before proceeding.

I would continue by connecting the scanner to the vehicle’s diagnostic connector and retrieving all stored codes and relevant freeze frame data. Consider noting this information before clearing the codes. 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 storage may need to worsen before an accurate diagnosis can be made.

If the code immediately resets, to complete the next step of your diagnosis, you will need to consult your vehicle information source for diagnostic flowcharts, connector pinout diagrams, connector face views, as well as component testing procedures and specifications. You can also use your vehicle information source to locate the exact position of the EAS fuel injector A.

Use the DVOM to test (voltage drop) the EAS control system power supply. Test fuses with the circuit loaded to avoid misdiagnosis. If proper power (battery voltage) and ground circuits are confirmed, use the scanner to activate the EAS fuel injector (solenoid) and test the output control circuit voltage. If voltage is insufficient, suspect a faulty controller or programming error.

If the output voltage circuit is within parameters, use the DVOM to test the specific EAS fuel injector. If the injector does not meet manufacturer specifications, suspect it has failed.

The EAS fuel injector is simply a solenoid injector that sprays reducing fluid into the exhaust
Remember to test ground circuits during voltage drop testing

How serious is this DTC?

A stored P20CE code should be considered serious and addressed as soon as possible. The EAS system may be damaged due to the conditions that contributed to storing the P20CE code.

What are some symptoms of the code?

Symptoms of a P20CE fault code may include:

• Decreased engine performance
• Excessive black smoke from vehicle exhaust
• Reduced fuel efficiency
• Other EAS/SCR related codes

What are some common causes of the code?

Causes

of this code may include:

• Faulty EAS fuel injector
• Open or shorted circuits in the EAS fuel injection control circuit
• Insufficient DEF in EAS tank
• Faulty EAS controller/PCM or programming error

What are the troubleshooting steps for P20CE?

A diagnostic scanner, digital volt/ohmmeter (DVOM), and vehicle-specific diagnostic information source will be needed to diagnose a P20CE 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.

I prefer to start my diagnosis with a visual inspection of EAS wiring harnesses and connectors. Burned or damaged wiring and/or connectors should be repaired or replaced before continuing.

I would continue by connecting the scanner to the vehicle’s diagnostic connector and retrieving all stored codes and relevant freeze frame data. Consider noting this information before clearing codes. 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 storing the code may need to worsen before an accurate diagnosis can be made.

If the code immediately resets, to complete the next step of your diagnosis, you’ll need to consult your vehicle information source for diagnostic flowcharts, connector pinout diagrams, connector face views, as well as component testing procedures and specifications. You can also use your vehicle information source to locate the exact position of the EAS fuel injector.

Use the DVOM to test (voltage drop) the EAS control system power supply. Test fuses with the circuit loaded to avoid misdiagnosis. If proper power (battery voltage) and ground circuits are found, use the scanner to activate the EAS fuel injector (solenoid) and test the output control circuit voltage. If voltage is insufficient, suspect the controller is faulty or has encountered a programming error.

If the output voltage circuit is within parameters, use the DVOM to test the EAS fuel injector in question. If the injector doesn’t meet manufacturer specifications, suspect it has failed.

The EAS fuel injector is simply a solenoid injector that sprays reducing fluid into the exhaust
Don’t forget ground circuits during voltage drop testing