Engine Control Module Ecm (limp Mode) Mystery Help


New Member
Dec 3, 2015
Ok guys, my back is up against the wall and I’m hoping this has happened to someone else that was able to itdentify the problem and get it fixed. I was driving home two months ago going about 70 mph on a relatively flat road when all of a sudden my 2007 Mustang GT seemed to shut down, but the engine was still running. I lost control of RPMs and wasn’t able to go more than 10 mph with the Check Engine light lite up along with a Wrench light which upon further research turned out to be the Electric Throttle Control (Limp Mode) light as identified in my owner’s manual. Got it towed straight to the dealership, where they informed me that I had a bad Engine Control Module (ECM) or as the dealership labeled it a Powertrain Control Module (PCM). So after the hefty price-tag to fix it, I figured go online and find it cheaper because the dealership stated this was not a part that was available new and I would have to purchase a remanufactured part anyways. I ordered it online and took the Cardone remanufactured ECM to them to install. They then informed me that the car was running again, but the ECM wasn’t allowing the Intake Control Motors to function properly stating that the ECM was no good. So, my next step was to send this one back and just send my in directly to Cardone through Autozone, to get rebuilt. I then contacted Autozone to follow up on status and they contacted Cardone, which in turn told Autozone that the ECM was good and not coming up with any errors. (Note that this is now the original ECM that came with the car that they are stating is OK) I’m pretty much out of options here and don’t know what else I can do at this point. Any suggestions would be greatly appreciated. ***Also, my Mustang is all stock, no upgrades or tunes.
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Jul 12, 2006
From your initial description it sounds like a bad electronic speed control motor. If you read your owners manual it explains what happens in the event the motor goes bad. Generally there is a engine service light accompanied with the wrench icon. These cars use a "drive by wire" type system and when the speed control (on the side of the throttle body) goes bad the car is programmed to go in limp mode so you can get of the road. Now that you have swapped ECMs around and that and the car is running it sounds like you have a new issue.