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Wierd LMM problems

N

NNYdiesel

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I've had a couple of odd problems with my 07 LMM. The first one is a starting issue. Somtimes it dies immediately after it starts. All I do is shut the truck off and then it will start back up again. It doesn't throw any codes and once it is started it runs fine. It happened twice in a row about 3 weeks ago. I took it to the dealer thinking that it could the old 07 operating system that could be causing it but it happened again on friday and I had the updated OS flashed onto my truck 2 weeks ago.

The next problem is sort of a funny one. I will driving down the road and for no apparent reason the widshield wipers will start spraying wiper fluid and the wipers will start going back and forth without me even touching the knob. Has anyone else had these problems before?
 
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You have the 07 classic OS loaded in there?

I would think somewhere it's communicating w/ the BCM and telling it to spray and turn on the wipers. I think you guys have a rain sensor but I don't think it turns on the sprayers just the wipers...
 
The operating system is the new 8594 system. I just had it flashed on by the dealership 2 weeks ago. I then pulled the tune out and put my normal driving tune in with the DPF codes turned off. I'm away from my flashscan right now and am unable to see what codes may be stored in there. I'll post up what I can find when I get home in an hour.
 
I had the wipers start spraying and running once. Just couldn't figure it out. It happened again, did I feel like a dummy when I figured it out. I was pressing a wrong button on the panel. It was the button for the heated washer fluid. LOL, this kind of thing can sure make a guy feel like a real idiot.
 
IIRC, the tune the dealer reflashed takes care of a problem with the anti-theft system in the LMM's. I know I saw a TSB floating around somewhere about it. I would re-build the tune using the newest tune as a base.

As far as the wiper thing, I wouldn't know where to start.
 
i havnt had any of those isues but i did have an isue with the tac. i was stuck in traffic and looked down and noticed at idle it was at 3000 but the motor sounded normal. turned the truck off when i got back and the tac was stuck at just over 2000. As i shut the truck on and off it slowly would creep down. now its back to normal i have no clue i tryed to disconnect the battery and that didnt help but now back to normal with no issues and i have no clue what it was.
 
What is odd is that it hasn't happened again since I posted about it. I checked for any codes and there are none and the windshield wipers have not acted up since either. I was able to get my hands on a set of GM repair manuals so maybe these might be able to shed some light on it.
 
I dont know about the newer trucks with rain sensors but the older GM's that would intermittenly turn on the wipers and washers was usually the wiper module or a bad ground. In your case i would go with the module.
 
DMitch said:
I had the wipers start spraying and running once. Just couldn't figure it out. It happened again, did I feel like a dummy when I figured it out. I was pressing a wrong button on the panel. It was the button for the heated washer fluid. LOL, this kind of thing can sure make a guy feel like a real idiot.
Click to expand...


I did the exact same thing....i didn't realize that switch was there until my cell phone hit it a few times..
 
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