Diagnostic Aids

WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

Check for the following conditions:

Check for the proper operation of the engines cooling system, including the correct coolant level.
A faulty thermostat that stays open slightly can cause DTC P1126 to set in cold weather when the vehicle is started and let sit while warming up. Replace any suspect thermostat.
Use the Temperature vs Resistance table in order to evaluate the possibility of a shifted ECT sensor. A shifted sensor could result in DTC P1126. Refer to Temperature Versus Resistance - Engine Coolant Temperature Sensor .
Check for a faulty electrical connection to the PCM.

An intermittent malfunction may be caused by a fault in the ECT sensor electrical circuit. Inspect the wiring harness and components for an intermittent condition. Refer to Intermittent Conditions .

Repair any electrical circuit faults that were found. Refer to Wiring Repairs .

If DTC P1126 cannot be duplicated, the information included in the Freeze Frame data can be useful in determining the vehicle operating conditions when the DTC was first set.