Severity and Diagnosis of Code P205A
How Severe Is Code P205A?
Diagnostic code P205A is considered severe and should be addressed immediately. It can disable the selective catalytic reduction (SCR) system and cause damage to the catalyst if not resolved promptly.
Symptoms of Code P205A
The most common symptoms associated with code P205A include:
- Reduced fuel efficiency
- Excessive black smoke from the exhaust
- Decreased engine performance
- Appearance of other SCR system-related codes
Possible Causes of Code P205A
This code can be triggered by several factors, including:
- A faulty reductant tank temperature sensor
- Open or shorted circuits in the temperature sensor system
- A defective SCR control module or PCM, or a programming error
Troubleshooting Code P205A
Diagnosing code P205A requires:
- A diagnostic scanner
- A digital volt/ohmmeter (DVOM)
- A vehicle-specific diagnostic information source
Step 1: Checking TSBs and Reading Codes
Consult the technical service bulletins (TSBs) for your vehicle model. Use a diagnostic scanner to retrieve stored codes and freeze frame data. Record this information before clearing the codes and perform a road test to see if the code resets.
Step 2: Testing the Reductant Temperature Sensor
Using a DVOM, test the temperature sensor according to the manufacturer’s specifications. Any sensor that does not meet the required parameters should be replaced.
Step 3: Inspecting Electrical Circuits
If the reductant temperature meets specifications and the code persists, test the input and output signal circuits between the sensor and the SCR/PCM controller. Before using the DVOM, disconnect all controllers to avoid damaging the system.
Conclusion
Error codes related to the reductant temperature sensor are often caused by a faulty sensor or connection issue. Thorough diagnosis helps effectively identify and repair the malfunction to ensure proper SCR system operation and prevent more severe catalyst damage.