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 MANUALSCHEVROLET2006COBALT SS, 4D SEDAN, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 343 (ENGINE CONTROL SYSTEM - 3.9L - TROUBLESHOOTING & DIAGNOSIS)FUEL SYSTEM DIAGNOSISCIRCUIT/SYSTEM VERIFICATION
2006 Chevrolet Cobalt SS, 4D Sedan, Standard
Circuit/System Verification
2006 Chevrolet Cobalt SS, 4D Sedan, StandardSECTION Circuit/System Verification
WARNING: This page is about a different car, the 2006 Chevrolet Monte Carlo and 2006 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT:
- Inspect the fuel system for damage or external leaks before proceeding.
- Verify that adequate fuel is in the fuel tank before proceeding.
- Turn ON the ignition, with the engine OFF.
- Command the fuel pump relay ON with a scan tool.
- If the fuel pump does not operate, refer to Fuel Pump Electrical Circuit Diagnosis .
- Turn OFF the ignition.
- Turn OFF all accessories.
- Install a J 34730-1A . Refer to Fuel Pressure Gage Installation and Removal .
- Turn ON the ignition, with the engine OFF.IMPORTANT:
- The fuel pump relay may need to be commanded ON a few times in order to obtain the highest possible fuel pressure.
- DO NOT start the engine.
- Command the fuel pump relay ON with a scan tool.
- Observe the J 34730-1A
with the fuel pump commanded ON. The fuel pressure should be 345-414 kPa (50-60 psi).
- If the fuel pressure is less than 345 kPa (50 psi), inspect for a restricted fuel feed pipe, poor connections at the harness connectors and ground circuits of the fuel pump, or a faulty fuel sender assembly.
- If the fuel pressure is more than 414 kPa (60 psi), replace the fuel sender assembly.
IMPORTANT: The fuel pressure may vary slightly when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant. - Monitor the J 34730-1A
for 1 minute. The fuel pressure should not decrease more than 34 kPa (5 psi).
- If the fuel pressure decreases more than 34 kPa (5 psi), continue with Circuit/System Testing.
- Relieve the fuel pressure to 69 kPa (10 psi).
- Monitor the J 34730-1A
for 5 minutes. The fuel pressure should not decrease more than 14 kPa (2 psi).
- If the fuel pressure decreases more than 14 kPa (2 psi), replace the fuel sender assembly.
- Remove the J 34730-1A . Refer to Fuel Pressure Gage Installation and Removal .
- Operate the vehicle within the conditions to reproduce the original symptoms.
- Monitor the O2 and the Fuel Trim parameters with a scan tool.
- If the scan tool parameters indicate a lean condition, inspect for a restricted fuel feed pipe, poor connections at the harness connectors and ground circuits of the fuel pump, or a faulty fuel sender assembly.
- If the scan tool parameters do not indicate a lean condition, go to Symptoms - Engine Controls .
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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.