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.
Fuel System Circuits
2000 Saturn LS AutomaticSECTION Fuel System Circuits
- Install fuel pressure gauge. See BASIC FUEL SYSTEM CHECKS . Turn ignition on. If pressure is 50-60 psi (3.5-4.2 kg/cm2 ), fuel quality may be cause of problem. If fuel pressure is not as specified, go to next step.
- If pressure is present but not within specification, diagnose fuel system. See FUEL SYSTEM in appropriate SYSTEM & COMPONENT TESTING article. If pressure is not present, go to next step.
- Turn ignition off. Remove fuel pump relay located in left-side instrument panel fuse block. Connect fused jumper wire between fuel pump relay battery feed circuit and fuel pump power feed circuit at relay cavities. Observe pressure gauge. If pressure is present, go to next step. If pressure is not present, go to step 6 .
- Remove jumper wire. Connect test light between ground and fuel pump relay control circuit at relay cavity. Using scan tool, command fuel pump relay on. If test light illuminates, go to next step. If test light does not illuminate, control circuit is shorted to ground or PCM is faulty.
- Connect test light between fuel pump relay control circuit and fuel pump relay ground circuit at relay cavities. Using scan tool, command fuel pump relay on. If test light illuminates, replace fuel pump relay. If test light does not illuminate, repair open in fuel pump relay ground circuit.
- Remove jumper wire. Connect test light between ground and fuel pump relay battery feed circuit at relay cavity. If test light illuminates, go to next step. If test light does not illuminate, check for open FUEL PUMP fuse (15-amp) or battery feed circuit. If fuse is open, check for shorted fuel pump power feed circuit or faulty fuel pump. Repair as necessary.
- Disconnect fuel pump harness connector. Connect fused jumper wire between fuel pump relay battery feed circuit and fuel pump power feed circuit at relay cavities. Connect test light between ground and fuel pump power feed circuit at fuel pump harness connector. If test light illuminates, go to next step. If test light does not illuminate, repair open in fuel pump power feed circuit.
- Connect test light between fuel pump power feed circuit and fuel pump ground circuit at fuel pump harness connector. If test light illuminates, replace fuel pump. If test light does not illuminate, repair open in fuel pump ground circuit.
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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.