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2005 Chevrolet Cobalt LS P0141 O2 Sensor Fault - Check Engine Light Returns After Replacement

Model: 05 Chevy Cobalt Fault Code: P0141 Posted: 2011-02-11 10:20

I own a 2005 Chevrolet Cobalt LS with a 2.2-liter 4-cylinder engine. The vehicle has triggered a check engine light, displaying fault code P0141, which indicates a malfunction in the post-cat oxygen sensor. I purchased this car secondhand and noticed the warning light was already on. I replaced the post-cat O2 sensor with an aftermarket unit and performed a battery disconnection to reset the system. However, after driving approximately 140 miles, the check engine light reappeared. The vehicle is currently required for registration, so I need a reliable fix as soon as possible. Any insights into potential causes or next steps would be greatly appreciated.

Related fault codes

P0141

Comments (3)

Anonymous 2011-02-11 11:11

Could you confirm whether you replaced the pre-cat or post-cat oxygen sensor? Where did you source the replacement—dealer or aftermarket? A basic check of the relevant fuses should be performed first. Please update us on your findings and progress.

Anonymous 2011-02-11 11:37

Thank you for clarifying—I replaced the post-cat O2 sensor, which was an aftermarket part. I’ve already inspected the fuses, and none appear to be blown or damaged.

Anonymous 2011-02-11 11:55

It's likely that the aftermarket oxygen sensor is not compatible with your 2005 Chevrolet Cobalt’s emissions system. If the electrical circuit checks out properly, it's recommended to replace the sensor with an OEM part from the dealership for optimal performance and reliability.