- Jul 5, 2023
- Reaction score
My son's 2001 Mustang GT automatic trans (4r70w) recently started acting up. Had an issue with what the shop thought was the fuel pump (erratic idle, stalling, pressure fluctuating) so a new fuel pump was installed. Upon starting it up, the car ran perfect so since I was at the shop, they had me test drive it. Made it onto the street and when the transmission shifted from 2nd to 3rd gear, it felt like someone mashed the brakes and was trying to power brake the car. you could feel the engine trying to push the car but it was bogging down as if the brakes were locked up. When I let off the accelerator and came to a stop, I could take off again like nothing ever happened until the 2-3 shift and it did the same thing. Prior to driving, the shop put a scanner on because they didn't realize the converters had been removed which throws a code. They told me they saw codes for the EGR (also removed), O2 sensors (due to converters), a security code and something about a shift solenoid code. They cleared all of the codes prior to driving and after driving and noticing the shifting problem, they tried the scanner but no codes were present. Not sure if it has anything to do with it but, the gear selector inside the car is also hard to move. Took it to another shop for transmission diagnosis, and it ran the same as before the fuel pump was replaced. When I turned the key on to the run position, it sounds like a relay under the hood clicking along with the fuel pump cycling in correspondence with the clicking under the hood. We're thinking the Constant Control Relay Module (CCRM) may be the culprit with the fuel pump and running issue since the fuel ump and filter have both been replaced. Has anyone had any experiences like this with their (4r70w)? I know the CCRM controls the cooling fan, A/C clutch, fuel pump power module, and provides power to the PCM, but does it also control other aspects such as the transmission? Thank you!