P0627

P0627-FUEL PUMP CONTROL CIRCUIT

P0627-Fuel Pump Control Circuit:

WHEN MONITORED
With the ignition on. Battery voltage greater than 10.4 volts.

SET CONDITION
An open or shorted condition is detected in the fuel pump control circuit. One Trip Fault. Three good trips to turn off the MIL.

POSSIBLE CAUSES
- (K31) Fuel pump control circuit shorted to battery voltage
- (K31) Fuel pump control circuit open
- (K31) Fuel pump control circuit shorted to ground
- TIPM
- PCM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test

1. FUEL PUMP OPERATION

Ignition on, engine not running.
With a scan tool in the Powertrain Actuators, actuate the Fuel Pump.

Q: Is the Fuel Pump operating?

YES: Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition
Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 2




2. FUEL PUMP CONTROL OPERATION FROM THE PCM

Turn the ignition off.
Disconnect the TIPM C2 harness connector.
Turn the ignition on.
Using the scan tool in the Powertrain Actuators, actuate the Fuel Pump.
With a 12-volt test light connected to ground, probe the Fuel Pump Control circuit in the TIPM C2 harness connector.

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

YES:

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

If OK, replace the TIPM. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 3




3. (K31) FUEL PUMP CONTROL CIRCUIT SHORTED TO BATTERY VOLTAGE

Stop the Fuel Pump actuation.
Turn the ignition off.
Disconnect the PCM C3 harness connector.
Turn the ignition on.
Measure the voltage of the (K31) Fuel Pump Control circuit at the TIPM C2 harness connector.

Q: Does the voltmeter indicate voltage present?

YES: Repair the short to voltage in the (K31) Fuel Pump Relay Control circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 4




4. (K31) FUEL PUMP CONTROL CIRCUIT OPEN

Turn the ignition off.

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 Control circuit from the TIPM harness connector to the appropriate terminal of special tool #8815.

Q: Is the resistance below 5.0 ohms?

YES: Go To 5
NO: Repair the open in the (K31) Fuel Pump Control circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test




5. (K31) FUEL PUMP CONTROL CIRCUIT SHORTED TO GROUND

Measure the resistance between ground and the (K31) Fuel Pump Control circuit in the TIPM C2 harness connector.

Q: Is the resistance below 100 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 6

6. 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