PCM/ECM/TCM Internal Temperature Too High


One of the system control modules has detected an internal temperature malfunction that could potentially prove catastrophic.

Code Set Parameters

Every control module is programmed with certain self-test and self-preservation data. The module over temperature function is designed to alert the driver of a potential serious internal malfunction. If the internal temperature of the module in question reaches a level that exceeds the manufacturer’s recommended specifications, a code will be stored and a service engine soon lamp will be illuminated.


Symptoms may vary between only a stored code and service engine soon lamp illumination to an engine stall and a no start condition. The conditions required to set this code are typically catastrophic for the module in question.

Common Causes

Far and away, the most common cause of this code being stored is a defective control module. Shorted wiring has also been known to contribute to this code being stored, in extreme and rare scenarios.

Common Misdiagnosis

Technicians report multiple control module failures are associated with shorted ground wiring to the affected module.


  • Several tools will be instrumental in attempting to successfully diagnose this code
  • A suitable OBD-II scanner (or code reader) and a digital volt/ohmmeter will be most helpful in trying to perform a successful diagnosis
  • Begin with a visual inspection of all wiring and connectors
  • Repair or replace damaged, disconnected, shorted, or corroded wiring, connectors, and components as necessary
  • Always retest the system after repairs are completed to ensure success. If all system wiring, connectors, and components (Including fuses) appear to be in normal working order, connect the scanner (or code reader) to the diagnostic connector and record all stored codes and freeze frame data
  • This information can be extremely helpful in diagnosing intermittent conditions that may have contributed to this code being stored
  • Continue by clearing the code and operating the vehicle to see if it returns
  • This will help to determine whether or not the malfunction is intermittent
  • After the codes are cleared, test drive the vehicle to see if the code returns
  • If the code fails to immediately return, you may have an intermittent condition
  • Intermittent conditions can prove to be quite a challenge to diagnose and in extreme cases may have to be allowed to worsen before a correct diagnosis can even be attempted
  • Individual control modules are equipped with integrated temperature sensors, to aid in self testing and self preservation strategies
  • Begin your diagnosis by testing all power and ground circuits for the affected module
  • Compare your findings with manufacturer’s specifications and make necessary repairs
  • Be sure to clear all trouble codes and retest the system in order to ensure that the condition is rectified
  • If all power and ground circuits align with the manufacturer’s specifications, suspect a faulty control module
  • Control module replacement will also require reprogramming it to match the vehicle.