Circuit Description

While the engine is warming, the powertrain control module (PCM) monitors the engine coolant temperature (ECT) sensor to determine how long it takes the engine to reach the coolant temperature required for Closed Loop operation. DTC P0126 will set if the PCM determines that the engine does not reach Closed Loop temperature in a specified amount of time. This test will not run if either the intake air or engine coolant temperature is too low at start-up. The PCM will only run this diagnostic trouble code (DTC) on a cold start and only once per cold start.