Topdown916

I'm trying to figure out if my shop is trying to cover it's tracks on a bad repair job. My 2002 Mustang GT threw a PO340 check engine code (supposedly for a fault in the cam position sensor). When I took it to the shop, they told me it wasn't the sensor or the wiring, and concluded that they had to replace my ECU for $900. The problem returned with the same code the next day. The day before I could take it back to the shop, the alternator blew completely. When I confronted them about the code returning and that they may have mis-diagnosed the problem, and the real problem was the alternator to begin with (see Ford Technical Service Bulletin 06-2-9 for more info on this type of problem), they claimed that the bad ECU is what ruined the alternator diode, and that a Ford technician they called confirmed that bad ECU's are the real problem. I don't think I'll ever know for sure because they replaced the ECU first. I think the shop is just trying to cover a $900 bad diagnosis, but I don't know enough to call their bluff. So far I paid the $900 and an extra $360 for the alternator job. Any ford mechanics with experience or knowledge on this one? The motor is stock, so there aren't any aftermarket complications to consider.

Brute03

that shop is screwing you big time. 98% of the time p0340 is caused by a faulty diode in the alt. that interferes with the cmp signal.

uberstang1

My brother had the same issue with his 01 GT, the cam shaft pos sensor code was set off by a bad alternator. The fact they they replaced the ECU and the code came back BEFORE the alt blew is a giveaway that the new ECU didnt correct you're problem the first time. If they claim the bad ecu killed you're alternator I would ask for the old ECU back try it with the the computer and see if it works. I never heard of a bad ECU killing an alternator.

WhiteFoxGT

You just got ripped man

SilvrStang

Dude I wish you were here in town Id def help you out on that one. This is the main reason why my car has never seen a shop other then my garage a few good trusty friends and my own toolset. Sorry about that man.