Jot51

short story.....09 mustang gt, dealer installed 3.73 rear end gear, speedo was off 10 MPH to fast, cruise control on vehicle worked fine, dealer then tried to reprogram cars computer to fix speedo to new gear which didnt work. Dealer re-installed factory settings to car but the cars cruise control will not even work. Has anyone had this problem and had it fixed?

thanks

p.s. got predator and fixed speedo myself.

2007VistaBlueGT

Dealer may have accidently turned off the cruise control. Take it back or to another dealer.

Jot51

ok thanks for the info.

hammeron

aside from a blown fuse, the only thing
that makes sense, is that there is conflicting
data to the PCM.

transmission output shaft rotational information.
axle ratio.
wheel/tire size.
revs per mile (if applicable).


i think maybe somewhere there is a discepency
and the PCM doesn't have a valid reference
point

Jot51

Everything was working fine with the cruise control while driving to the dealership, except being 10 mph off. When the mechanic hooked up their laptop to my vehicle if removed stock settings, then he (mechanic) tried downloading pmc specs. for a re running a 3.37 gear and the laptop was downloading KR500 specs. Then the vehicle wouldnt crank at all. So.....machanic redownloaded the GT specs into the PCM, then thats when i noticed cruise control wasnt working on the way home.
Im wondering that too about the PCM not fully taking the downloaded specs. Theres no "engine light", no "codes". Wondering if it could be a clutch or brake disengade switch, or vehicle speed sensor? Might even be the "on off " switch on streering wheel.

Thanks Hammeron for your reply.

hammeron

well for sure you have to take it back
to the dealership, i don't think this is
going to be something you can fix at
home.

it's almost as if the cruise control option,
was not part of the uploaded file

wicked stang

same exact thing happened to me
they installed the gears and tried to charge me $95 for the reprogram when i got it back.
i had them take the $95 off my bill because they didn't tell me about it and my speedo was still off anyway.
they had a hard time trying to reprogram the speedo settings and fixing the cruise control because the car kept wiping the tune off the computer but they eventually got it and it worked fine after that.

Jot51

yeah youre right. least the dealership did all of the work and is under warranty. Its just the wait, they (dealership) have had the car longer then i have.

Jot51

Hey wicked stang, how long did they keep trying to redownload the program to your car? if you know.

wicked stang

they probably tried for about two hours and they didn't get it. then they tried the next morning and got it immediately. they were saying something about internet connection problems, but i dont know.