Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET2000CHEVY EXPRESS G3500, VAN CARGO EXTENDED, 6.5 FREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROLS - BASIC DIAGNOSTIC PROCEDURESNO START DIAGNOSISNO START-ENGINE CRANKS OKAY (6.5L DIESEL)FUEL PUMP ELECTRICAL CIRCUIT
2000 Chevrolet Chevy Express G3500, Van Cargo Extended, 6.5 F
Fuel Pump Electrical Circuit
2000 Chevrolet Chevy Express G3500, Van Cargo Extended, 6.5 FSECTION Fuel Pump Electrical Circuit
- Perform OBD system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in appropriate SELF-DIAGNOSTICS article. After performing OBD system check, go to next step.
- Turn ignition off for 10 seconds. Turn ignition on. Fuel lift pump should run during glow plug cycle. If fuel lift pump runs, see BASIC SYSTEM CHECK . If fuel lift pump does not run, go to next step.
- Remove fuel pump relay located in underhood electrical center. Using fused jumper wire, jumper fuel pump relay battery feed circuit and fuel lift pump power feed circuit together at fuel pump relay cavities. If fuel lift pump runs, go to next step. If fuel lift pump does not run, leave jumper wire connected and go to step 8.
- Turn ignition on. Using test light connected to ground, probe fuel pump relay battery feed circuit at relay cavity. If test light illuminates, go to next step. If test light does not illuminate, go to step 10.
- Connect test light between fuel pump relay battery feed circuit and fuel pump relay ground circuit at relay cavities. If test light illuminates, go to next step. If test light does not illuminate, go to step 11.
- Using test light connected to ground, probe fuel pump relay control circuit at relay cavity. Turn ignition off for 20 seconds. Turn ignition on. If test light illuminates during glow plug cycle, and then turns off, go to next step. If test light does not illuminate, and then turn off, go to step 12.
- Check for faulty connections at fuel pump relay. Repair as necessary. After repairs, go to step 18. If connections are okay, go to step 13.
- Disconnect fuel lift pump harness connector at fuel lift pump. Using test light connected to ground, probe fuel lift pump power feed circuit at harness connector (vehicle side). If test light illuminates, go to next step. If test light does not illuminate, go to step 15.
- Using test light connected to battery voltage, probe fuel lift pump ground circuit at fuel lift pump harness connector (vehicle side). If test light illuminates, go to step 14. If test light does not illuminate, go to step 16.
- Repair open in fuel pump relay battery feed circuit. After repairs, go to step 18.
- Repair open in fuel pump relay ground circuit. After repairs, go to step 18.
- Check for open or short to ground in fuel pump relay control circuit between PCM and fuel pump relay. Repair as necessary. After repairs, go to step 18. If circuit is okay, go to step 17.
- Replace fuel pump relay. After repairs, go to step 18.
- Replace fuel lift pump. After repairs, go to step 18.
- Repair open or high resistance in fuel lift pump power feed circuit between fuel pump relay and fuel lift pump. After repairs, go to step 18.
- Repair open in fuel lift pump ground circuit. After repairs, go to step 18.
- Replace PCM. Perform PCM replacement procedures. After repairs, go to next step.
- Using scan tool, clear DTCs. Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not start, or starts and stalls, go to step 2.
- Allow engine to reach normal operating temperature. Using scan tool, select DTC, FAILED THIS IGN function. If any DTCs are set, diagnose DTCs. See appropriate SELF-DIAGNOSTICS article. If DTCs are not set, go to next step.
- Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any other DTCs are set that have not been diagnosed, diagnose DTCs. See appropriate SELF-DIAGNOSTICS article. If DTCs are not set, system is okay.
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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.