I got in my car to start it up (2006 Chevy Equinox) and found that I couldn’t shift it into drive. I could physically maneuver the shifter- but it didn’t actually shift into drive. Also I should note that shifting into reverse caused a heavy “clunk” sound in the transmission, but the gear seemed to work normally otherwise. There was a bunch of warning lights on my dash so I got out my code reader and got the following codes:

1. P0171 - System Too Lean (think this is maybe unrelated, an o2 sensor I’ve been meaning to replace)

2. P0200 - Transmission Control System (Mil Request)

3. P1125 - Manufacturer Control (google says problem with the accelerator?)

4. P2138 - Throttle/Pedal Position Sensor/Switch D/E Voltage Correlation

5. P0700 - Transmission Control System (Mil Request)

6. P1125 - same as #3

7. P2138 - same as #4

I was out of town for a family visit and needed to get back home by Monday so I was pressed to find a temporary fix. All the codes seemed to have the ECM module in common so I just unplugged it and plugged it back in. Car then starts up fine, seems to work normally and drive normally, I took it to a gas station to fuel up for a return commute. When I restarted my car I got the same codes, and same issues. Could not engage drive, heavy clunk noise when I shifted to reverse. I did the same thing to the ECM, and car worked normally once again, was able to drive it all the way home. I had a 4 hour drive and didn’t see anything weird with my RPMs, no abnormal fuel usage or anything, and the performance seemed normal too. So am I right to suspect the computer is faulty? I’ve heard that a computer failure is abnormal. I’m pretty good at fixing electronics but not so handy with mechanical stuff so I’m wondering if I’ve got bias here as to what’s wrong. Is this a job for a shop or is it just a faulty computer?