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.
Diagnostic Procedures
2001 Chevrolet Cavalier LS, 2.4 TSECTION Diagnostic Procedures
WARNING: This page is about a different car, the 2003 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.
- Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM.
- Does the engine start and continue to run? If yes, go to next step. If no, go to step 4.
- Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see INTERMITTENT CONDITIONS under SELF-DIAGNOSTIC SYSTEM.
- Turn ignition ON, with engine OFF. Lift and support vehicle. Disconnect CKP sensor harness connector. Measure the voltage between the CKP sensor 12-volt reference circuit and a good ground. Is voltage near battery voltage? If yes, go to next step. If no, go to step 7.
- Measure voltage between the CKP sensor 12-volt reference circuit and the CKP sensor low reference circuit. Is voltage near battery voltage? If yes, go to next step. If no, go to step 8.
- Connect test light between the CKP sensor signal circuit and 12-volt reference of CKP sensor. Does the fuel pump operate when ignition voltage is applied to the CKP sensor signal circuit? If yes, go to step 11. If no, go to step 9.
- Test for an open or short to ground in 12-volt reference circuit of CKP. Did you find and correct the condition? If yes, go to step 15. If no, go to step 14.
- Test for an open CKP low reference circuit. Did you find and correct the condition? If yes, go to step 15. If no, go to step 14.
- Test CKP sensor signal circuit for an open, a short to ground or a short to voltage. Did you find and correct the condition? If yes, go to step 15. If no, go to next step.
- Test for an intermittent and/or poor connections at the CKP sensor. Did you find and correct the condition? If yes, go to step 15. If no, go to next step.
- Remove CKP sensor and inspect CKP sensor for the following conditions:
- Excessive air gap between the CKP sensor and the reluctor wheel.
- Physical damage.
- Improper installation.
- Electromagnetic interference in the CKP sensor circuits.
- Foreign material passing between the CKP sensor and the reluctor wheel.
Did you find and correct the condition? If yes, go to step 15. If no, go to next step.
- Inspect CKP reluctor wheel for proper installation, damage or looseness. See appropriate article in ENGINES. Did you find and correct the condition? If yes, go to step 15. If no, go to next step.
- Replace CKP sensor. See CRANKSHAFT POSITION SENSOR under SENSORS in REMOVAL & INSTALLATION - CORVETTE article. Perform the CKP System Variation Learn Procedure. See CRANKSHAFT POSITION SENSOR under PROGRAMMING. Did you complete the replacement? If yes, go to step 16.
- Replace PCM. See POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION - CORVETTE article. Did you complete the replacement? If yes, go to next step.
- Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition cycle? If yes, go to step 2. If no, go to next step.
- Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, 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.