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 2002 Pontiac Sunfire and 2002 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
- Perform diagnostic system check - engine controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
- Is the cooling system low on coolant? If yes, check and repair cause of coolant loss. If no, go to next step.
- Turn ignition off. Disconnect the ECT sensor. Connect a 3-amp fused jumper wire between the signal circuit and the low reference circuit of the ECT sensor. Turn ignition on, with engine off. With a scan tool, observe the ECT sensor temperature. Does the scan tool indicate that the ECT sensor temperature is more than 280°F (138°C)? If yes, go to step 7 . If no, go to next step.
- Turn ignition off. Disconnect the ECT sensor. Connect a 3-amp fused jumper wire between the signal circuit of the ECT sensor and a known-good ground. Turn ignition on, with engine off. Observe the ECT sensor temperature with a scan tool. Does the scan tool indicate that the ECT sensor temperature is more than 280°F (138°C)? If yes, go to next step. If no, go to step 6 .
- Test the ECT sensor low reference circuit for high resistance or an open. Repair the circuit as necessary. After repairs, go to step 10 .
- Test the ECT sensor signal circuit for high resistance or an open. Repair the circuit as necessary. After repairs, go to step 10 .
- Remove the ECT sensor. Suspend the ECT sensor and a thermometer in a pan of water. Place the pan on a burner or hot plate. Test the resistance of the ECT sensor through the specified range of 50-194°F (10-90°C). Does the resistance and temperature closely match? See appropriate SENSOR RESISTANCE table in appropriate SENSOR OPERATING RANGE CHARTS article. If yes, go to next step. If no, go to step 9 .
- Reinstall the ECT sensor. When complete, diagnose thermostat operation.
- Replace the ECT sensor. After replacing sensor, go to next step.
- Clear the DTCs with a scan tool. Turn ignition off for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See CONDITIONS FOR RUNNING DTC . Does the DTC run and pass? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
- Using scan tool, observe the stored information and Capture Info. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs are displayed, 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.