Diagnostic Aids
WARNING: This page is about a different car, the 2002 GMC Sierra and 2002 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
- A DTC P0128 is designed to detect a faulty thermostat.
- A skewed ECT sensor may cause a P0128 to set.
- A skewed IAT sensor may cause this DTC to set.