How severe is this DTC?
Any stored diesel particulate filter code can be a precursor to a clogged exhaust system. The stored code P200C should be considered severe and addressed as quickly as possible. 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 P200C fault code may include:
- Decreased engine performance
- Excessive black smoke from vehicle exhaust
- Reduced fuel efficiency
- Other emission-related codes
What are some common causes of the code?
Causes
of this code may include:
- Non-functioning SCR system
- Faulty SCR injector
- Incorrect or insufficient DEF fluid
- Faulty exhaust temperature sensor
- Incorrect SCR controller or programming error
- Pre-catalyst exhaust leaks
- Installation of aftermarket or high-performance exhaust parts
What are the P200C troubleshooting steps?
If SCR codes are also stored, these should be addressed before attempting to diagnose the stored P200C. Pre-catalyst exhaust leaks must be repaired before attempting diagnosis for this type of code.
You will need access to a diagnostic scanner, a digital volt/ohmmeter (DVOM), an infrared thermometer with a laser pointer, and a source of vehicle-specific diagnostic information to diagnose a P200C 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 useful diagnostic information.
You’ll want to start 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.
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 now), 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 infrared thermometer to gather actual temperatures before and after the diesel particulate filters. Observe the scanner data stream to compare your actual results with the information found on the scanner data display screen. Also compare exhaust temperature sensor data between engine banks. If exhaust temperature inconsistencies are detected, test the respective sensors using the DVOM. Sensors not meeting manufacturer specifications should be considered faulty.
If all sensors and circuits appear to be functioning as expected, suspect that the diesel particulate filter is defective or the SCR system is malfunctioning.
Ensure the DEF tank is filled with the appropriate fluid and that the SCR system is operating as expected…