2002 sierra problems

I installed a 550esp on a 2002 gmc sierra about a month ago and maybe a week later, the check engine light came on, the dealer said it was a recall for the transmission and they took care of it and then on my way home it came on again. Back to the dealer and they said the remote start was causing it by shutting down the transmission computer, I don't deny that the alarm/installation was the cause, but they ripped out the entire alarm without telling me untill I saw it on the seat going home. I spent so much time doing automatic windows/locks/remote start/a mercury switch for the toolbox, everything. And the cut out almost the entire thing. My question is has anyone heard of this, what I could have done wrong, I used the 555l thought I had everything right because everything worked perfectly up untill the took it out. has anyone heard of this? If I reinstall it what can I do to make sure it won't happen again. thanks For listening

It sounds like you didn't hook up the second ignition wire. This wire controls other electonics and must be powered up when the vehicle starts. If the 550 is newer it has a relay already wired in the relay pack. It is the pink/white wire coming from the relay pack and needs to go to the white second ignition wire in the wiring harness.Certified Security Specialist

Always check info with a digital multimeter.

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I agree w/ auex! I've heard that the secondary ignitions control the transmission controller. If not hooked-up correctly, it can prevent the vehicle from shifting into higher gears. I heard an instance in which a truck wouldn't shift beyond second gear.Friends Don't Let Friends Bump Stock.

Yup you definetly need to hook up the 2nd ignition wire a white wire the same gauge as the other main wires under the steering column

thanks for the help guys, I have a feeling you are right, I just wish the dealer wouldn't have pulled the whole thing out, now I have to reinstall the entire alarm instead of just one wire   thanks   

Yes, most mechanics are electrical idiots. They have no idea what wire does what on a car alarm, and they refuse to admit it.....so they just eliminate everything. But I guess you have to look at it like this: If the problem was your fault, but they covered it under warranty....well, I guess you're still ahead. After all, they could have charged you for the repair. On the other hand, if they charged you a bunch of money AND tore your install apart, well, you should be mad at them...but there is probably not much you can do.