2002 Rendevous won't shift

This vehicle just had a used transmission installed and it wont shift correctly. When in drive it starts out in third gear, and once up to about 30mph it shifts into second. Then at forty it shifts to third for a few seconds and then goes into limp in mode, which is back to second gear. Reverse operates normally. Typically the limp in or failsafe modes for an electronically controlled transmission will give you one forward gear, which is what ever gear both shift solenoids turned on creates, and you will have reverse, neutral and park. All of these are commanded by the manual valve which is directly linked to the shifter cable. The computer in the car was setting a P1875 for the pressure control solenoid circuit open.

To test for the cause of that code, the technician needs to access the PCM which is inside the air cleaner housing. On connector #2 pins 44 light blue / white, and 45 red / black provide the feed power to the solenoid and the ground return to the PCM. By unplugging the connector at the PCM the resistance of the circuit can be measured and the circuit was open. The next step is to find out where and why the circuit is open and then plan to do the repair. One of the easiest things to do is to remove the connector at the transmission and jumper the two pins together and then ground one at the PCM connector and provide power through a small lamp. In this case something that draws 1.5 to 2 amps such as a brake lamp bulb. The lamp lit up confirming that the wiring was OK, and that means that the problem is inside the transmission or with the connector itself.


The following two pictures are screen shots captured with my bore scope.

The red arrows point out the damaged pins, note the second one on the top, right hand row and the fourth one are pushed out of place, while the third is bent up out of line.

Most of the time when a connector is damaged like this it isn't a big deal to disassemble and repair it. Unfortunately with the way this connector for the transmission harness is assembled, that's going to mean that the transmission will have to come apart to access the other side of the connector.