P0253

P0253-INJECTION PUMP FUEL CONTROL CIRCUIT LOW





For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

The Powertrain Control Module (PCM) provides a PWM driver circuit and ground circuit to the Fuel Control Actuator (FCA). The PCM varies the current to this valve to provide the correct fuel flow to the High Pressure Pump based on operating conditions. The FCA is a normally open valve. High circuit resistance may cause fuel pressure to be higher than commanded at light loads. Excessive current draw or a short circuit will cause the PCM to turn the driver off during the remainder of that ignition cycle. The PCM will not turn the driver back on until the ignition is cycled off, and back on, and the current draw or short circuit is gone. The PCM illuminates the MIL lamp and the ETC lamp immediately after the diagnostic runs and fails. During this time the customer may experience low power. The PCM turns off the MIL lamp after the diagnostic runs and passes in four consecutive drive cycles.

- When Monitored:
Continuously when the engine is running.

- Set Condition:
The Powertrain Control Module (PCM) does not detect system voltage on the (K366) FCA Driver circuit when the PWM signal is turned on.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. ACTIVE DTC
1. Ignition on, engine not running.
2. Record freeze frame data and clear DTCs.
3. Turn the ignition off for 75 seconds.
4. Start the engine and let idle for at least two minutes.
5. With the scan tool, read DTCs.

Did the DTC reset?

Yes

- Go To 2

No

- Refer to the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test

2. CHECK THE (K365) FUEL CONTROL ACTUATOR DRIVER CIRCUIT FOR A SHORT TO GROUND




1. Turn the ignition off.
2. Disconnect the PCM C1 harness connector.
3. Disconnect the Fuel Control Actuator harness connector.
4. Measure the resistance between ground and the (K365) FCA Driver circuit at the FCA harness connector.

Is the resistance below 10k Ohms?

Yes

- Repair the (K365) FCA Driver circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 3

3. CHECK FOR THE (K365) FCA DRIVER CIRCUIT SHORTED TO THE (K366) FCA RETURN CIRCUIT




1. Measure the Resistance between the (K365) FCA Driver circuit and the (K366) FCA Return circuit at the Fuel Control Actuator harness connector.

Is the resistance below 10k Ohms?

Yes

- Repair the short between the (K365) FCA Driver circuit and the (K366) FCA Return circuit.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 4

4. FUEL CONTROL ACTUATOR
1. Reconnect the PCM C1 harness connector.
2. Replace the Fuel Control Actuator.
3. Turn the ignition on and clear any DTCs.
4. Start the engine and allow it to idle for at least two minutes.
5. With the scan tool, read DTCs.

Did the DTC reset?

Yes

- Replace the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Repair complete.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.