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2003 Impala P0137 and P0141 O2 Sensor Codes: Diagnosis and Fix

Model: 2003 Impala Fault Code: P0137 Posted: 2015-04-04 18:29

Hello, I own a 2003 Chevrolet Impala with 170,000 miles. The check engine light came on and the vehicle is showing fault codes P0137 and P0141. I replaced both original oxygen sensors with Bosch units, but the codes persist. I then swapped the post-catalytic converter O2 sensor with a factory OEM unit, yet the check engine light remains on. Should the light turn off if the sensors were faulty? Or is a code reset via an OBD-II scanner required? I attempted disconnecting the battery, but that did not resolve the issue. I verified the 15-amp fuse for the O2 sensor heater circuit and confirmed it is intact. What should I check next to diagnose or fix this problem? Thank you for any guidance.

Related fault codes
P0137P0141
Comments (6)
Anonymous 2015-04-05 06:21

Buehler? Hello?

Anonymous 2015-04-05 09:59

Check the rear O2 sensor connector for battery voltage across the heater pins and ensure the internal resistance of the sensor heater is within specifications.

Anonymous 2015-04-05 15:39

Thanks for the info. I don't have a wiring diagram—could you please specify which two wires should have 12V? And what resistance value should I expect from the new O2 sensor?

Anonymous 2015-04-05 16:06

The heater wire is pink, ground is black, and the tan-tan-white wire carries the sensor signal.

Anonymous 2015-04-05 18:40

OK, thanks. I'll check this tomorrow.

Anonymous 2015-04-06 15:36

I found only 6V DC at the rear O2 sensor connector. After tracing the wiring back to the main harness and cleaning all connectors, the check engine light turned off. Thanks for your help!