The Powertrain Control Module (PCM) manages many critical vehicle functions, including cooling fan operation. When the PCM receives incorrect sensor data or develops an internal fault, it may command the radiator fans to run continuously as a fail-safe strategy. While bad temperature sensors, wiring issues, and relay failures are more common causes, PCM problems should not be overlooked when diagnosing cooling fan concerns.
Before blaming the PCM, technicians should inspect:
At AutoPCMS, every module is tested using professional equipment to determine whether the PCM is correctly processing sensor inputs and controlling outputs. If a fault is found, we can often repair the original module, helping customers avoid unnecessary replacement costs.
If your cooling fans run constantly and other components have already been tested, the PCM may require professional evaluation. AutoPCMS offers PCM testing, repair, and replacement solutions for many vehicle makes and models.
