P127C

P127C-FUEL PUMP CONTROL CIRCUIT 2 LOW - DIESEL

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

- When Monitored:
With the ignition on. Battery voltage greater than 10.4 volts.

- Set Condition:
A shorted low condition in the Fuel Pump Control circuit has been detected by the TIPM. One Trip Fault. Three good trips to turn off the MIL.





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

1. FUEL PUMP OPERATION
1. Ignition on, engine not running.
2. With a scan tool under the ECM Actuators, actuate the Fuel Pump.

Is the Fuel Pump operating?

Yes

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.

No

- Go To 2

2. FUEL PUMP CONTROL OPERATION FROM THE ECM




1. Turn the ignition off.
2. Disconnect the C1 TIPM harness connector.
3. Ignition on, engine not running.
4. Using the scan tool under the ECM Actuators, actuate the Fuel Pump.
5. With a 12-volt test light connected to ground, probe the (K31) Fuel Pump Control circuit in the TIPM C1 harness connector.

Does the test light illuminate brightly and flash on an off?

Yes

- Go To 3

No

- Perform the Diagnostic Procedure for P0629-FUEL PUMP CONTROL CIRCUIT HIGH, P0629.

3. (A109) FUEL PUMP CONTROL OUTPUT CIRCUIT SHORTED TO GROUND




1. Turn the ignition off
2. Disconnect the C10 TIPM harness connector.
3. Disconnect the Fuel Pump Module harness connector.
4. Measure the resistance between ground and the (A109) Fuel Pump Control Output circuit at the Fuel Pump Module harness connector.

Is the resistance below 100 Ohms?

Yes

- Repair the short to ground in the (A109) Fuel Pump Control Output circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 4

4. FUEL PUMP MODULE




1. Connect the C1 and C10 TIPM harness connectors.
2. Ignition on, engine not running.
3. Using the scan tool under the TIPM Actuators, actuate the Fuel Pump.
4. With a 12-volt test light connected to ground, probe the (A109) Fuel Pump Control Output circuit at the Fuel Pump Module harness connector.

Does the test light illuminate brightly and flash on and off?

Yes

- Replace the Fuel Pump Module.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 5

5. TOTALLY INTEGRATED POWER MODULE

NOTE: Before continuing, check the TIPM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

1. Using the schematics as a guide, inspect the wire harness and connectors.
2. Pay particular attention to all Power and Ground circuits.

Were any problems found?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Replace the Totally Integrated Power Module.
- Perform the BODY VERIFICATION TEST. Body Verification Test.