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 387 (ENGINE CONTROL SYSTEM - 3.9L - DTC P0442 TO DTC P2A01)DTC P2A01CIRCUIT/SYSTEM TESTING
2006 Chevrolet Cobalt SS, 4D Sedan, Standard
Circuit/System Testing
2006 Chevrolet Cobalt SS, 4D Sedan, StandardSECTION Circuit/System Testing
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.
- With the engine running at operating temperature, observe the affected HO2S sensor parameter with a scan tool and manipulate the related wiring and connectors. Manipulation should not affect the parameter.
- If manipulation does affect the parameter, then repair the harness or connector.
- With the ignition ON, the engine OFF, and the sensor disconnected, measure for approximately 4 mV from the affected HO2S sensor low signal circuit to ground.
- If more than approximately 4 mV, test the affected HO2S sensor low signal circuit for a short to voltage or a faulty control module.
- If less than approximately 4 mV, test the affected HO2S sensor low signal circuit for high resistance or for a faulty control module.
- With the ignition ON, the engine OFF, and the sensor disconnected, measure for approximately 412 mV from the affected HO2S sensor high signal circuit to ground.
- If more than approximately 412 mV, test the affected HO2S sensor high signal circuit for a short to voltage or a faulty control module.
- If less than approximately 412 mV, test the affected HO2S sensor high signal circuit for a short to ground, high resistance, or for a faulty control module.
- With the ignition ON, the engine OFF, and the sensor disconnected, install a 3-amp fused jumper between the affected HO2S sensor high signal circuit and the affected HO2S sensor low signal circuit. The affected HO2S parameter should indicate 0 mV.
- If all circuits and connectors test normal and the affected HO2S parameter does not indicate 0 mV, replace the control module.
- With the ignition ON, the engine OFF, and the sensor disconnected, install a test lamp between the affected HO2S sensor high signal circuit and battery voltage. The affected HO2S parameter should indicate approximately 1106 mV.
- If all circuits and connectors test normal and the affected HO2S parameter does not indicate 1106 mV, replace the control module.
- If the control module and all circuits test normal, replace the affected HO2S sensor.
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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.