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.
Mechanical Inspection: Diagnosis
2001 Chevrolet Cavalier LS, 2.4 TSECTION Diagnosis
WARNING: This page is about a different car, the 2003 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.
- Remove Heated Oxygen Sensor (HO2S) in front of catalytic converter. Install Backpressure Tester (J 35314-A) in place of HO2S. Start engine and allow it to reach normal operating temperature. Record the exhaust system backpressure reading. If backpressure does not exceed 1.25 psi (8.6 kPa), go to next step. If backpressure is more than 1.25 psi (8.6 kPa), go to step 3 .
- Increase engine speed to 2000 RPM and note backpressure. If reading exceeds 1.25 psi (8.6 kPa), go to next step. If reading does not exceed 1.25 psi (8.6 kPa), go to step 6 .
- Turn ignition switch to OFF position. Remove backpressure gauge and install HO2S. Remove post-catalyst HO2S and install backpressure gauge. Start engine and let idle. Note backpressure. Increase engine speed to 2000 RPM and note backpressure. If reading exceeds 1.25 psi (8.6 kPa), go to next step. If reading does not exceed 1.25 psi (8.6 kPa), go to step 5 .
- Check exhaust system for collapsed pipe, debris, heat distress, 2-layer exhaust pipe separation and possible internal muffler internal failure. Replace as necessary. After repair, go to 6 .
- Replace catalytic converter. After repair, go to next step.
- Remove the backpressure gauge and reinstall the HO2S sensor. Clear DTCs. Road test the vehicle in order to verify the repair.
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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.