ECM Service Precautions

The ECM is designed to withstand normal current draws associated with vehicle operations, however, care must be used to avoid overloading any of these circuits. In testing for opens or shorts, do not ground or apply voltage to any of the ECM circuits unless instructed to do so by the diagnostic procedures. These circuits should only be tested using the High Impedance Multimeter (J-29125 or J-34029A) if they remain connected to the ECM.

Whenever a ECM removal and replacement is performed, follow the procedure in PFI CHART C-1: ECM REPLACEMENT CHECK  . The "ECM Replacement Check" will check for vehicle conditions that could damage a new ECM when it is installed in the vehicle.