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Q: Car decelerating to complete stop

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The Wrench light comes on. When this happens, the car decelerates to a complete stop.

A: Hi. The light you are referring to is the p...

Hi. The light you are referring to is the powertrain malfunction warming light. This light will illuminate whenever the control module determines there is a fault in the system. There are many reasons this light might come on. However, there are a couple of sensors inside the transmission that commonly fail and turn on the malfunction light. These are the output shaft speed sensor (OSS) and turbine shaft speed sensor (TSS). If these parts are indeed the problem, there will be corresponding diagnostic trouble codes (DTCs) stored in the modules memory. These codes can be retried by a technician with a scan tool. There is also a technician service bulletin (TSB) regarding the failure of these sensor. It is number 07-21-11.

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