So my son's Mazda 3 started throwing code P0758, transmission was on limp mode. I cleared the codes, and nothing, as soon as I put the car into D, codes came back.
I research a little online and most of the people pointed to the TCM module being bad. These 2.0l cars don't have a TCM, the tranny is controlled by the PCM.
Before I went ahead and ordered a replacement PCM I performed a wire continuity test from the PCM plug to the Plug in the transmission, test passed, then I checked the resistance of the solenoids, and the test passed, then I supplied 5V to the solenoids and I could hear the solenoids click, so the test passed.
I ended up ordering a re manufactured PCM and after dealing win the damn PATS (My son only has 1 key) I was able to start the car. Codes were gone, and car was shifting perfect in the driveway. I took it for a test drive, and everything was good.
My son left, and 20 minutes later, he called me and said that the car is doing the same thing again. Transmission in limp mode, AT and MIL lights on.
I still have to pull the codes to make sure the code is be the same. But I am pretty sure it will be.
My question is, can a "faulty" solenoid keep blow one of the lines in the PCM? Or could be something else?
What I am thinking is that the solenoid might get "shorted" maybe intermittently and blow the PCM line?
Should I replace the solenoid before playing with a new PCM?
There is nothing else in between the PCM and the solenoid to be causing this issue. Just the wires.
Any suggestion will be appreciated.