P0627

P0627-FUEL PUMP RELAY CIRCUIT

P0627-Fuel Pump Relay Circuit:

WHEN MONITORED
With the ignition on. Battery voltage greater than 10.4 volts and the ASD sense switch is on.

SET CONDITION
Actual Fuel Pump Relay state is not equal to desired state. One Trip Fault. Three good trips to turn off the MIL.

POSSIBLE CAUSES
- (A916) Fused B+ circuit
- (F942) Fused ignition switch output circuit
- (K31) Fuel pump relay control circuit
- (K31) Fuel pump relay control circuit shorted to ground
- Fuel pump relay
- PCM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test

1. FUEL PUMP RELAY OPERATION

Ignition on, engine not running.
With a scan tool, actuate the Fuel Pump Relay.

Q: Is the Fuel Pump Relay operating?

YES: Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Component Tests and General Diagnostics
Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 2

2. FUEL PUMP RELAY

Turn the ignition off.
Remove the Fuel Pump Relay from the IPM.
Measure the resistance of the Fuel Pump Relay Coil.

Q: Is the resistance between 70 to 90 ohms?

YES: Go To 3
NO: Replace the Fuel Pump Relay. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test




3. (A916) FUSED B+ CIRCUIT

Ignition on, engine not running.
Using a 12-volt test light connected to ground, probe the (A916) Fused B+ circuit.

Q: Does the test light illuminate brightly?

YES: Go To 4
NO: Repair the open or short to ground in the (A916) Fused B+ circuit. Inspect the related fuse and repair as necessary. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test




4. (F942) FUSED IGNITION SWITCH OUTPUT CIRCUIT

Ignition on, engine not running.
Using a 12-volt test light connected to ground, probe the (F942) Fused Ignition Switch Output circuit.

Q: Does the test light illuminate brightly?

YES: Go To 5
NO: Repair the open or short to ground in the (F942) Fused Ignition Switch Output circuit. Inspect the related fuse and repair as necessary. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test




5. (K31) CONTROL CIRCUIT OPEN

Turn the ignition off.
Disconnect the C3 PCM harness connector.

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

Measure the resistance of the (K31) Fuel Pump Relay Control circuit from the IPM to the appropriate terminal of special tool #8815.

Q: Is the resistance below 5.0 ohms?

YES: Go To 6
NO: Repair the open in the (K31) Fuel Pump Relay Control circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test




6. (K31) CONTROL CIRCUIT SHORTED TO GROUND

Measure the resistance between ground and the (K31) Fuel Pump Relay Control circuit in the IPM.

Q: Is the resistance below 100 ohms?

YES: Repair the short to ground in the (K31) Fuel Pump Relay Control circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 7

7. PCM

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

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

Q: Were there any problems found?

YES: Repair as necessary. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Replace and program the Powertrain Control Module. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test