P0627

P0627-FUEL PUMP RELAY CIRCUIT





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

Theory of operation

The Fuel Pump Relay is controlled by the Powertrain Control Module (PCM). The PCM controls the fuel pump relay by grounding the (K31) Fuel Pump Control circuit.

- When Monitored:
With the engine running and the battery voltage greater than 10.4 Volts.

- Set Condition:
The Powertrain Control Module (PCM) detects that the actual state of the fuel pump control does not match the intended state.





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

1. DTC IS ACTIVE

NOTE: If there are any ASD/Main Relay or system voltage DTCs present, diagnose those DTCs before proceeding with this test procedure.

1. Ignition on, engine not running.
2. With the scan tool, select View DTCs. Copy DTC and Freeze Frame information and clear DTCs.

NOTE: Active or pending DTCs may not allow Fuel Pump actuation, ensure all DTCs are cleared before proceeding with this test procedure.

3. With the scan tool, actuate the Fuel Pump.
4. Monitor the scan tool for at least two minutes.
5. With the scan tool, select View DTCs.

Is the status Active for this DTC?

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test

2. FUEL PUMP RELAY
1. Turn the ignition off.
2. Install a known good Fuel Pump Relay.
3. Turn the ignition on.
4. Using a scan tool, erase the DTC.
5. Attempt to start the engine.

Does the DTC return?

Yes

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

No

- Go To 3

3. (K31) FUEL PUMP RELAY CIRCUIT SHORTED TO GROUND BETWEEN THE PDC AND PCM




1. Turn the ignition off.
2. Remove the Fuel Pump Relay.
3. Disconnect the PCM C1 harness connector.
4. Measure the resistance between ground and the (K31) Fuel Pump Control circuit at the PCM C1 harness connector.

Is the resistance below 1000 Ohms?

Yes

- Repair the short to ground in the (K31) Fuel Pump Control circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 4

4. (K31) FUEL PUMP RELAY CIRCUIT OPEN OR HIGH RESISTANCE
1. Measure the resistance of the (K31) Fuel Pump Control circuit between the Fuel Pump Relay connector (at terminal 86) and the PCM C1 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 5

No

- Repair the open or high resistance in the (K31) Fuel Pump Control circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

5. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Power Distribution Center (PDC) and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the related connectors.
4. Perform any Technical Service Bulletins that may apply.

Were any problems found?

Yes

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

No

- Replace and program the Powertrain Control Module (PCM). PCM/ECM Reprogramming
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.