P0629 HIGH VOLTAGE DETECTED AT THE FUEL LIFT PUMP
When Monitored and Set Condition:
When Monitored: While the key is on.
Set Condition: The commanded signal to the lift pump does not match the feedback signal from the lift pump.
POSSIBLE CAUSES
- LOOSE CONNECTION
- (K62) SUPPLY CIRCUIT SHORTED TO VOLTAGE
- (K62) SUPPLY CIRCUIT SHORTED
- LIFT PUMP
- ECM
DIAGNOSTIC PROCEDURE
-
With the DRBIII®, in system test actuate the lift pump. Does the lift pump run?
Yes --> Go To 2
No --> Go To 5 -
Lift pump actuation still running. While the lift pump is running, wiggle the wiring harness and connectors throughout the circuit. Does this interrupt the pump operation?
Yes --> Repair the loose connection.
No --> Go To 3 -
Disconnect the ECM harness connectors.
NOTE: Check connectors - Clean/repair as necessary.
Measure the resistance between the lift pump (K62) supply circuit of the lift pump connector and battery negative. Is the resistance greater than 100k Ohms?
Yes --> Go To 4
No --> Repair the (K62) supply circuit shorted to voltage. -
Measure the resistance between the lift pump (K62) supply circuit and all other circuits in the ECM harness connectors. Is the resistance greater than 100k Ohms?
Yes --> Go To 5
No --> Repair the (K62) supply circuit shorted to another circuit. -
Reconnect the disconnected Lift pump harness connector. Reconnect the ECM harness connectors. Turn the ignition on. With the DRBIII®, read DTCs while disconnecting the lift pump. Did P0628 set?
Yes --> Replace the lift pump.
No --> Replace the ECM