I had a trans code right after buying my '97 Bravada. I had bought a scanner and service manual so I could do some work myself and after getting the code, I pulled & wiggled the 20 wire connector then ran my hand between all the wires and the trans in case the insulation on a wire had worn on a piece of casting flash. I didn't disconnect the connector, just worked it to get the pins to move in the sockets and hopefully got a better connection. I then reset the trouble code and drove the car without another episode for a few years. Since, I've had a troublesome O2 sensor code come in every few months although I haven't found the cause. The scanner has paid for itself a few times just on this car but it's good on friends cars too.
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