Unplug fuel pump relay. Turn ignition on. Check for battery voltage at fuel pump relay connector terminals No. 1 (Blue/Black wire) and No. 5 (Black/White wire).
If battery voltage is present at terminals No. 1 and 5, go to next step. If battery voltage is not present, check wiring connectors and 15-amp fuse in relay block.
Disconnect fuel pump harness connector and fuel pump control unit harness connector. Check continuity of Orange/Blue wire between fuel pump relay, fuel pump and fuel pump control unit.
Check continuity of Green/Orange wire between fuel pump control unit and ECM connector terminal No. 6. See Fig 1 . Check continuity of Pink/Black wire between fuel pump relay and ECM connector terminal No. 18. Check continuity of Pink/Blue wire between fuel pump control unit and ECM connector terminal No. 19.
Repair wiring as necessary. If no faults are found in wiring, test fuel pump relay. See RELAYS under RELAYS & SOLENOIDS. Also test fuel pump, fuel pump control unit and inspect ECM connector pin terminals.

Fig 1: Identifying ECM Harness Connector Pin Terminals (Q45)

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Fuel Pump Control System Wiring