The SCR (Selective Catalytic Reduction) system injects diesel exhaust fluid into the exhaust gases accurately. It increases the temperature of the Diesel Particulate Filter to work efficiently. This process makes the filter have a longer service life and reduces the emissions coming from the exhaust. This entire system is monitored by the PCM or another independent controller that interfaces with the PCM. Regardless, the controller monitors the Oxygen Sensor, Oxides of Nitrogen Sensor, and Exhaust Temperature Sensors to determine the appropriate timing of the reducer information.
If the PCM notices that the Selective Catalytic Reduction System for bank number 1 of the engine is unstable in operation, the P204F OBDII fault code will be set.
The SCR System wires or connectors may have damage that causes a short or open circuit.
The Diesel Exhaust Fluid supplied to the system may not be adequate.
The pressure sensor may be faulty.
Possibly the injector of the reduction system is damaged.
The SCR System controller may have a programming error or is faulty.
Possible solutions of the DTC code P204F Generic
To troubleshoot the P204F OBDII diagnostic code, try this:
To get started, consider the Technical Service Bulletins.
Check that all electrical components of the SCR System are in good condition. If you detect wires or connectors with damage that causes a short, they should be repaired if necessary.
Use a multimeter, test the Reductant Pressure Sensor according to the guidelines in the service manual. If you determine that the values are not within the allowable range, replace the sensor.
If the system pressure is right, use a multimeter to test the input and output signal circuits between the Selective Catalytic Reduction System sensors and the PCM. An out-of-range value indicates damage to the wiring, so you should make repairs.