Technical Service Bulletins

Avoiding TCM damage

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Avoiding TCM damage

It has been found during warranty part reviews of the TCM (Transmission Control Module) at the Warranty Parts Center that the TCM is possibly being shorted to battery voltage during vehicle diagnosis and/or repairs when the vehicle is being serviced.

It has been found that if the positive battery jump start post/terminal cover is removed and/or missing, and the TCM comes into contact with the positive battery jump start post/terminal during diagnosis and/or service, the TCM will be damaged and will require replacement.

This TSB applies to the following vehicles:

* 2005-2010 Chevrolet Cobalt

* 2006-2010 Chevrolet HHR

* 2006-2010 Chevrolet Express

* 2006-2010 GMC Savana

* 2005-2006 Pontiac Pursuit (Canada)

* 2007-2010 Pontiac G5

* 2005-2007 Saturn Ion


Prior to removing the TCM from its mounting bracket, disconnect the negative battery cable. If service requires the negative battery cable to be installed for diagnostic purposes, unplug the TCM before it is removed from its mounting bracket. Unplugging the TCM will eliminate the possibility of damaging the module during diagnosis and/or repair.

The control module may be damaged when the metal case contacts battery voltage. DO NOT contact the control module metal case with battery voltage when servicing a control, using battery booster cables, or when charging the vehicle’s battery. DO NOT use the TCM or its mounting bracket/fasteners as a ground connection when jump-starting.

The location of the positive battery jump post/terminal for each vehicle (excluding Express and Savana) is shown in the following illustrations. Do not allow any part of the TCM to come into contact with the positive battery jump start post/terminal.

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