Diagnostic Test
- Perform On-Board Diagnostic (OBD) System Check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in TESTS W/CODES
article. After performing OBD system check, go to next step.
- Remove gas cap. Turn ignition switch to RUN position. Listen for fuel pump operation. If fuel pump operates for about 3 seconds, go to next step. If fuel pump does not operate for about 3 seconds, go to step 4).
- Turn ignition switch to LOCK position. Remove fuel pump relay located behind left side of glove box. Using a test light connected to battery voltage, probe terminal No. 3 (Pink/Black wire) at fuel pump relay harness connector. See Fig 1
. Turn ignition switch to RUN position. Observe test light while cranking engine. If test light does not illuminate, go to step 17). If test light illuminates, perform FUEL SYSTEM PRESSURE DIAGNOSIS
.
- Turn ignition switch to LOCK position. Remove fuel pump relay. Turn ignition switch to RUN position. Using test light connected to ground, probe terminal No. 2 (Blue/Black wire) at fuel pump relay harness connector. See Fig 1
. If test illuminates, go to next step. If test light does not illuminate, go to step 9).
- Turn ignition switch to LOCK position. Connect a fused jumper wire between terminals No. 2 (Blue/Black wire) and No. 4 (Pink/Black wire) at fuel pump harness connector. Turn ignition switch to RUN position. If fuel pump does not operate, go to next step. If fuel pump operates, go to step 12).
- Leave fused jumper wire connected. Ensure ignition switch is in RUN position. Using a test light connected to ground, backprobe terminal No. 2 (Pink/Black wire) at fuel pump harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 10).
- Turn ignition switch to LOCK position. Remove fused jumper wire. Disconnect fuel pump harness connector. Using a test light connected to battery voltage, probe terminal No. 1 (Black wire) at fuel pump harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 11).
- Replace fuel pump and go to step 19).
- Repair open or short in Blue/Black wire between main relay and fuel pump relay harness connectors and go to step 19).
- Repair open or short in Pink/Black wire between fuel pump relay and fuel pump harness connectors. After repairs are complete, go to step 19).
- Repair open in fuel pump ground circuit and go to step 19).
- Turn ignition switch to LOCK position. Remove fused jumper wire. Turn ignition switch to RUN position. Using a test light connected to ground, probe terminal No. 1 (Black/White wire) at fuel pump relay harness connector. If test light does not illuminate, go to next step. If test light illuminates, go to step 15).
- Using a test light connected to battery voltage, probe fuel pump relay terminal No. 3 (Pink/Black wire). Observe test light while cranking engine. If test light does not illuminate, go to next step. If test light illuminates, go to step 16).
- Using a test light connected to battery voltage, backprobe fuel pump relay control circuit (Pink wire) at PCM harness connector. Observe test light while cranking engine. If test light illuminates, go to step 17). If test light does not illuminate, go to step 18).
- Repair open or short in Black/White wire between FI fuse and fuel pump relay harness connector and go to step 19).
- Replace fuel pump relay and go to step 19).
- Check fuel pump relay control circuit (Pink wire) for open or short, between PCM and fuel pump relay harness connectors. If open or short does not exist, go to next step. If open or short exists, repair as necessary and go to step 19).
- Replace PCM and go to next step.
- Attempt to start engine. If engine starts, system operating properly at this time. If engine does not start, check the following and repair as necessary:
- Fuel feed hose leaking or plugged.
- Poor connection at PCM.
- Poor connection at fuel pump.
Courtesy of GENERAL MOTORS CORP.