I have a 2012 GT which I bought used last April. Sunday it began having starting issues and when I check under the red rubber problem hider I found that the positive terminal was nearly disintegrated from corrosion.


So Monday I took it to the dealer. They said the battery and the engine harness needed to be replaced. Unfortunately it was just out of warranty (38 months and 29,500 miles on it) so it cost me nearly 1000$ to fix it.


But here is the trouble. After I got it back the button on the shifter no longer disables overdrive, it does nothing. Also, the MPG reading increases each time I drive it, so now it says I get over 40 MPG.


I told the service writer and he speculated it was a fuse.


Can anyone here come up with a better idea? I am guessing they plugged something up wrong.


Thanks

 

not a mechanic anymore, but something doesn't sound right about replacing an engine harness because the battery terminal corroded. Even if the battery cable was corroded they should be able to address that without replacing engine harness.

in any event I would go back to the dealer and and have them look at the problem.

I noticed you had a thread about changing the shifter, anything to do with the problem you are describing here ?

 

The service tech said the corrosion had made its way down the cables and it was pretty easy to see that it had. I read about at least one other case on this forum where the engine harness needed to be replaced as well.


The shifter replacement is different. There is some slight damage on the top of the shifter (only affecting the looks of it) that was done by the original owner I presume. I am replacing it just to make it like new.

 

I took it back in today. The service writer wanted to replace the shifter. I told him that it was not the shifter. So he said they will continue checking.
I could see this going bad. The overdrive/hill button was working when I took it in and they said they did not do anything with the shifter the last time it was in. So I was losing faith in their ability to diagnose this.
So I asked for a meeting with the service manager. He seemed to be a very nice man. As I was telling him about all that had happened and how I felt about the suggestion that I needed to buy a new shifter when the service writer came into the office.
He said they had found that the battery harness they had installed was for a manual transmission so it had no overdrive/hill button wiring on it. wow which was sort of what I suspected.
The service manager had him get my car ready asap and order the proper harness. He said I would get a free loaner and the service would be done without cost. They will call me when the harness is there and I will take it in.


good thing it worked out

 

Dealerships scare me these days. They just seem to find more problems with your car than you knew you had. Glad/hope its getting fixed properly the second time.