P0627-FUEL PUMP CONTROL CIRCUITFor a complete wiring diagram Refer to Section 8W.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 state is not equal to desired state. 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 SHORTED TO GROUND(K31) FUEL PUMP CONTROL CIRCUIT OPENTIPMPCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).Diagnostic Test1.FUEL PUMP OPERATIONIgnition on, engine not running.With a scan tool in the PCM, actuate the Fuel Pump.Is the Fuel Pump operating?YesRefer to the INTERMITTENT CONDITION Diagnostic Procedure.Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoGo To 22.(K31) FUEL PUMP CONTROL CIRCUIT SHORTED TO VOLTAGEStop 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?YesRepair the short to voltage in the (K31) Fuel Pump Control circuit.Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoGo To 33.(K31) FUEL PUMP CONTROL CIRCUIT OPENTurn the ignition off.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?YesGo To 4NoRepair the open in the (K31) Fuel Pump Control circuit.Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)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?YesRepair the short to ground in the (K31) Fuel Pump Control circuit.Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoGo To 55.FUEL PUMP CONTROL OPERATION FROM THE PCMTurn 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?YesBefore continuing, check the TIPM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.If OK, replace the TIPM in accordance with the Service Information.NoGo To 66.PCMBefore 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?YesRepair as necessary.Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoReplace and program the Powertrain Control Module per Service Information.Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)