Dash symbols but no problem

Tiny
STEVE620
  • MEMBER
  • 2007 GMC ENVOY
  • 4.2L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 115,000 MILES
Every now and then 4 dash symbols light up for a short time then go off. It was happening every other day, but it has not come on for about a week. I'm not getting any codes and everything seems to working okay.
Saturday, July 11th, 2020 AT 12:07 PM

11 Replies

Tiny
STEVE W.
  • MECHANIC
  • 12,963 POSTS
With all 4 coming on it is likely you have an issue with one of the ABS wheel speed sensors.
If there is a fault in one it will turn off the ABS/Traction control and turn those lights on. What are you using to read the codes? If the lights come on there will be a stored history code at least, however it may not show up on some tools.
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Saturday, July 11th, 2020 AT 6:31 PM
Tiny
STEVE620
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  • 60 POSTS
I"m using Blue Driver reader.
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Wednesday, July 15th, 2020 AT 12:13 PM
Tiny
STEVE W.
  • MECHANIC
  • 12,963 POSTS
Okay, that should be able to read the ABS module, at least they claim it will. GM had had an issue with the front ABS wiring failing and turning the lights on. What you might try would be to have someone set in the truck while you go along the wiring harness from the sensor to the frame and along the frame doing a wiggle test. You just move the wire around and gently tug on it and the connectors. If the lights come on while you are doing the test you have found the culprit.
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+1
Wednesday, July 15th, 2020 AT 1:20 PM
Tiny
STEVE620
  • MEMBER
  • 60 POSTS
Thank you will try that.
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Wednesday, July 15th, 2020 AT 2:00 PM
Tiny
STEVE W.
  • MECHANIC
  • 12,963 POSTS
Good luck, please keep us informed if you find the problem. Intermittent faults can drive you batty searching.
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Thursday, July 16th, 2020 AT 5:22 PM
Tiny
STEVE620
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  • 60 POSTS
I did what you said with the wires but nothing. It has been about 2 weeks now and no lights. If it should happen again will stop car and do the same. If the sensor was starting to go bad would this happen?
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Thursday, July 16th, 2020 AT 5:27 PM
Tiny
STEVE W.
  • MECHANIC
  • 12,963 POSTS
Not usually. This is a common issue with wiring though. It will come and go with no real cause. Hit a bump and the lights come on, hit the same bump and no lights, turn left and they come on, next time they don't. I would keep the scan tool in the truck, if they come on, try to get any codes or better yet look at the live data for the ABS speed sensors, say you are moving at 30 mph, they all should read the same, if you have one that reads 15 or zero, that is the corner to look at.
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Thursday, July 16th, 2020 AT 6:30 PM
Tiny
STEVE620
  • MEMBER
  • 60 POSTS
I just found the problem, it turns out that the Body Control Module (BMC) was doing some crazy things. I took the car to a GMC Dealership to check out. They told me that there is nothing wrong with the BMC. I have a Dash Cam in the vehicle and I was getting power for it from the OBD2 port, I purchased this cable from Amazon. I removed the cable, after a day of driving the car the radio started to play again, then the dash lights went out. Now all is good. GM told me that this is a known thing to happen when you use the port that way.
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Monday, October 5th, 2020 AT 5:09 PM
Tiny
STEVE W.
  • MECHANIC
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Thanks for the update. That is a different find, I wonder if the camera uses the port for more than just power, does it capture things like time date speed and braking events? That could explain why it was causing problems. If it was only getting power then it would likely plug into the power socket.
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Monday, October 5th, 2020 AT 5:45 PM
Tiny
STEVE620
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The camera only get power from the port.
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Tuesday, October 6th, 2020 AT 2:59 AM
Tiny
STEVE W.
  • MECHANIC
  • 12,963 POSTS
Strange. The OBD port uses the same power feed as the lighter, unless there is some type of feedback on the ground side. Keep us posted if the issue stays gone or returns. Thanks again.
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Tuesday, October 6th, 2020 AT 7:46 AM

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