P0627-FUEL PUMP CONTROL CIRCUIT





For a complete wiring diagram Refer to Section 8W.



Possible Causes
(K31) FUEL PUMP CONTROL CIRCUIT SHORTED TO BATTERY VOLTAGE
(K31) FUEL PUMP CONTROL CIRCUIT SHORTED TO GROUND
(K31) FUEL PUMP CONTROL CIRCUIT OPEN
TIPM
PCM


Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).



Diagnostic Test

1. FUEL PUMP OPERATION

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

Is the Fuel Pump operating?

Yes


No

2. (K31) FUEL PUMP CONTROL CIRCUIT SHORTED TO VOLTAGE



Stop the Fuel Pump actuation.
Turn the ignition off.
Disconnect the C3 PCM harness connector.
Disconnect the C1 TIPM harness connector.
Ignition on, engine not running.
Measure the voltage on the (K31) Fuel Pump Control circuit at the C1 TIPM harness connector.

Does the voltmeter indicate voltage present?

Yes


No

3. (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 C1 TIPM harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?

Yes


No

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



Measure the resistance between ground and the (K31) Fuel Pump Control circuit in the TIPM C1 harness connector.

Is the resistance below 100 ohms?

Yes


No

5. FUEL PUMP CONTROL OPERATION FROM THE PCM



Turn the ignition off.
Connect the C3 PCM harness connector.
Ignition on, engine not running.
Using the scan tool in the PCM, actuate the Fuel Pump.
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


No

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.

Were there any problems found?

Yes


No