2002 Chevy Impala Fault Code PO128

2002 CHEVROLET IMPALA
73,000 MILES • 6 CYL • FWD • AUTOMATIC
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OMBENA
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  • 1 POST
PO128 appeared on my car while driving down the highway. I cleared the code with my MemoScanner (no freeze codes) and have driven the car 2-300 miles without any code coming on. Yesterday I drove the car on a 100 mile trip and checked the coolant operating temperature with my scanner and it was 88Celsius/190F. It indicates cool but it appears it's running at normal operating temperature. Does this mean the temperature sensor is bad?

Thanks, OMB
Dec 7, 2009 at 9:16 AM
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MMPRINCE4000
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  • 8,548 POSTS
Either the coolant temp sensor or the thermostat.

Chevy has had some problems with the temp sensor, especially on the inline 6 with the temp sensor malfunctioning.
Dec 11, 2009 at 10:04 AM