Diagnostic Aids
WARNING: This page is about a different car, the 2002 Pontiac Firebird and 2002 Chevrolet Camaro. However, it is still accessible from the selected car via links, so may be relevant.
DTC P0125 is designed to detect a skewed ECT sensor.
If a DTC P0125 and a P0128 are set, a faulty thermostat may be the cause, M/T.