I just installed a remote start on a 00 Sierra. I am having problems with the anti theft bypass module. The bypass connects to the purple data wire at the diagnostic port under the dash. For some reason the truck is not responding to the bypass. I even tried a second bypass module and its still doing the same thing. I emailed DEI tech support, and everything they told me to check, I had already checked. They are as confused as I am. I mentioned that the truck was tuned, and that said its possible that the tune has "locked" the computer and will not allow it to bypass the anti theft. They said I would have to ask Nelson if they lock the computer with their tunes. Well, does anyone know if they lock the computer with their tunes? The owner of the truck called Nelson, and the woman who answered quickly said that the only way it can interfere with a remote start is if a SES light is on. I know that's the case with newer OEM remote starts, but an aftermarket doesn't pay attention to that light. I just need to know if Nelson locks the computer or any settings when they do a tune.

 

They used to but I am not sure if they still do. Call them and ask them if they lock the PCM. A lot of tuners do.

 

I had a similiar problem like this and it was fixed by the guy that tunes my truck. Forgot how he did it but they should be able to help you

 

I'm just trying to make sure I'm not going crazy here. Being that I installed and programmed two separate bypass modules and the computer STILL would not let the engine start. I can not think of ANY explanation other than the tune.

 

I hope one of the tuners from Nelson sees this and chimes in, it usually takes someone other than the secretary a couple days to call back.

 

I put a DEI remote start on my 2001and I had a Nelson mail order, no problems. That said, I do think the ecm that I got was locked, at least I think it was. I don't remember telling Nelson that I had the remote start, so I doubt he changed anything because of it.

 

What bypass module did you use? Did you use a bypass that connects directly to the Passlock wires at the steering column? Or a bypass that connects to the databus wire?

 

I used the ExpressKit PLJX and I think I connected to the Passlock wires that go from the steering column to the BCM. It's been a little bit and I sold that truck, but I connected it exactly as the instructions sheet had shown and it worked fine. I didn't connect to any part of the diagnostic port, as you have said, everything was from the ignition wires, BCM and ECM.

GM Self Learning (ALL TYPES) Passlock Override

 

I think a PLJX will solve this problem, because it connects directly to the Passlock wires at the steering column. So it will bypass the Passlock signal before it even gets to the PCM. The two modules I used before (and have used dozens of times in the past on other GM vehicles) connect to the purple data wire at the diagnostic port under the dash. Doing that sends a signal to the PCM to bypass the Passlock. But they didn't work on this truck because Nelson locked the PCM.

 

I just wanted to update this. I installed a PLJX the other day the the engine fired right up after the install. Just as I hoped, this bypass worked just fine because it doesn't connect directly to the PCM wire. It connects to the Passlock wires at the steering column and duplicates the Passlock signal and sends that to the PCM. So this is the only type of bypass module that will work if you have a Nelson Performance tune. The only other option is to jump thru hoops with Nelson and have them unlock the PCM.