I was hoping someone could help me. I was having that "visit workshop fault" that most guys on this forum were attributing to a bad front control module. I got a new module from the dealer and replaced it but still had the fault. So I thought I may need to clear the code so I bought a durametric reader and it's saying it's the "rear control unit". Does anyone know where that is? I'd like and try to replace it this week but I don't even know where to start. Any help would be appreciated.

 

Isn't the rear unit behind the rear seats in the speaker box? I seem to recall that is where the ECU is. There were some posts about how to access that if I recall correctly.

 

The dealer is telling me it's under the drivers seat. I guess i'll start there...

 

yes, it is under the driver's seat, under a cover that is mounted to the floor pan.

picture credit to Atomic80

 

Thanks! Much appreciated!!!

 

No problem, just as a heads up, the cover is mounted with pinch tabs on the side closest to the rear seats. They are difficult to get to while the driver's seat is still in the car, but doable. Also, there isn't much play in the wires for the wiring harnesses, so be careful with any tugging/pulling while trying to remove the box containing the module

 

Good to know. Would it be easier to remove the seat or is it just going to be a pain either way?

 

I personally didn't want to mess with the harnesses connected to the bottom of the seat, or worry about scratching any interior pieces trying to lift the seat out of the car. With enough light and an idea of how the cover is held in place, it really isn't too bad with the seat still in place. Obviously, the mounting bolts for the seats need to be removed, and the seat tilted back as far as possible.

With an extra set of hands to help lift the seat, it would be 10x easier to see what you are doing. Just be sure to use plenty of towels to cover up center console/steering wheel/door sills so you don't scratch anything

 

NY Outlaw,

Thanks for your help. Was fairly easy to get too/replace. I've cleared most of the faults but a few remain. Any suggestions to fix c121 c128 8015 c130 and 8004. I belive c121/128 are related to the calibrating the steering sensor and 8004/8015 is terminal 30 voltage supply? I've attempted to calibrate the steering sensor but it just won't clear. I have no idea what terminal 30 is.

 

unfortunately, I can't help with the fault codes. I replaced my rear control unit solely because I upgraded to the 997.2 OEM LED taillights, then had the dealer code the control unit so the lights would work properly.