P0627

P0627-FUEL PUMP RELAY CIRCUIT

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

- When Monitored:
With the engine running and 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.

Diagnostic Test

1. DIAGNOSTIC TROUBLE CODE (DTC) IS ACTIVE
1. Attempt to start the engine. If the engine will not start, crank the engine for five seconds.

WARNING:
When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.

2. Using the scan tool, read the active DTCs.

Does the scan tool display P0627-FUEL PUMP CONTROL CIRCUIT/OPEN?

Yes

- Go To 2

No

- Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.
- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.

2. (K31) FUEL PUMP CONTROL CIRCUIT SHORTED TO ANOTHER VOLTAGE SUPPLY CIRCUIT
1. Turn the ignition off.
2. Remove the Fuel Pump Relay from the Power Distribution Center (PDC).
3. Disconnect the Powertrain Control Module (PCM) C1 harness connector.
4. Measure the resistance between the (K31) Fuel Pump Control circuit and all other 5 volt and 12 volt supply circuits at the PCM C1 harness connector.

Is the resistance above 1000 Ohms between the (K31) Fuel Pump Control circuit and all other 5 volt and 12 volt supply circuits?

Yes

- Go To 3

No

- Repair the (K31) Fuel Pump Control circuit for a short to the circuit that measured below 1000 Ohms.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

3. (K31) FUEL PUMP CONTROL CIRCUIT SHORTED TO GROUND
1. Measure the resistance between ground and the (K31) Fuel Pump Control circuit in the Fuel Pump harness connector.

Is the resistance below 100 Ohms?

Yes

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

No

- Go To 4

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

Is the resistance below 5.0 Ohms?

Yes

- Go To 5

No

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

5. FUEL PUMP
1. Connect the PCM C1 harness connector.
2. Turn the ignition on.
3. With the scan tool, actuate the Fuel Pump control to the ON position.
4. Using a 12-volt test light connected to ground, check the (K31) Fuel Pump Control circuit in the Fuel Pump harness connector.

NOTE: The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.

5. With the scan tool, actuate the Fuel Pump control to the OFF position.
6. Using a 12-volt test light connected to ground, check the (K31) Fuel Pump Control circuit in the Fuel Pump harness connector.

NOTE: The test light should not be illuminated.

Is the test light illuminated and bright with the actuation ON (100%) and not illuminated with the actuation OFF (0%)?

Yes

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

No

- Go To 6

6. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Fuel Pump 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.
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). .
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.