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U-Turn Master
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239 Posts
Discussion Starter #1
2003 GMC 1500HD

Since I installed my drop I've had an ABS Light on. I think this is what has caused my Traction control to be disabled. Yesturday I did some trouble shooting and found no obvious broken wires, sensors looked good etc.

I am assuming that when installing the kit, my front lines got stretched past the acceptable limit.lol I tried to keep slack, but I would not be suprised if I pulled something loose.

That being said, while troubleshooting I disconnected the The Sensor on each side one at a time, with the truck running. When the pass side was disconnected the BRAKE light lit up and the bing bing bing alarm went off. Reconnected it and went to the drivers side, disconnected it and nothing. What does this say? I checked the connectors and wiring for anything visual and saw nothing obvious. Last night while driving the alarming started again, this makes be believe that I must have been in the right area, must be a loose wire. My next step is to replace the drivers side sensor and pigtail, does this sound like the right direction? Any idea about part numbers?
 

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Check your wheel speed sensors and see if they have any crap on them. Youd be surprised just how many ABS lights I fix by cleaning the sensors. Also, you probably have a hight sensing pro valve in the rear. check that to see if everything is OK there. If you can get your hands on a scanner, see if there are codes stored. Try to use a scanner that will let you look at the ABS system, not one of those cheap code readers.
 

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U-Turn Master
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239 Posts
Discussion Starter #3
Thanks for the reply, sensors are clean, Let me know some more info on this height sensing proportioning valve. First I've heard of this. Does it check for a certain amount of rake?

Also, does a good Scanner pull ABS codes that are more specific than "ABS System Failure"

Thanks for the help, I was starting to think we were without a service tech. lol
 

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If all the wiring is good ( not broken, harness connections still good ) I'd look at the sensors. I cleaned them good with brake cleaner. They get little metal filing on them soometimes. THe codes can trip but not go away. I had a dealer reset mine when I went in for an oil change for a Jimmy, so they didn't charge. Not light since. ( my problem was the wire had the rim. fixed it, but lights will stay on until reset )
 

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U-Turn Master
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239 Posts
Discussion Starter #5
Thanks for the help, I'm gonna pull them and clean them up good again. and have the codes reset. If I do need to replace the sensors, does anyone know the part numbers I should be looking for?
 

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What is the exact code that is stored in the ECM? As for the hight sensing pro valve, is senses the rear end ride hight. It can tell if you are running loaded or not and if so how much. it is connected to the axle and frame. If you are loaded, the distance between the two points is less. It then determins how much to limit the pressure to the rear brakes. Less load, less pressure. it prevents rear wheel lock up. I have seen these things make the brake sys do wierd things.
 

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U-Turn Master
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239 Posts
Discussion Starter #7
I haven't been able to pull the codes yet, that's next and I will report back. The ride height pro valve sounds interesting. I did have the rear lowered before I replaced the Control arms up front (Only had drop keys at the time) And had no problems with ABS at all. It's been giving me the lights since the first startup after the Control arms were installed, but I will look into it.....Thanks.
 

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U-Turn Master
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239 Posts
Discussion Starter #8
Still haven't been able to pull the codes, but I did clean the sensors and inspect all wires again. Damn Bing Bing Monster went crazy. Stated kicking on and off and kicked me out of 4WS, that's the last straw lol. Happened several times, then I unhooked the sensor to the drivers front (the one I suspected that I stretched) and the cutting in and out quit. Looks like there must be a bad connection somewhere in that pigtail. I guess I've found my problem. Now just need to find a replacement.
 
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