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Discussion Starter #1
2004 Tahoe Z-71 175K miles

So I get in the car tonight to run an errand and the ABS light is on under the tach. I THINK that's airbag not sure tho... When I get out there is a noise coming from behind the driver front tire THAT SOUNDS LIKE a small electric motor running with bad bearings, or a small water pump run dry... The abs light is the only thing new going on and directly coincides time-wise. I had to disconnect the battery just now as whatever is running under there would obviously drain it overnight...

I did pop the hood real quick but nothing jumped out at me. The sound is louder by the driver front tire that when listening from the top of the engine compartment...

Anyone...?
 

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ABS light is the anti-lock brake system, not the airbag. It sounds like your wheel sensor is triggering something with the ABS, so I would start there. Not sure about the noise, maybe someone else can chime in
 

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Edit: the ABS control module is located on the driver’s side driver’s seating area. Maybe it is malfunctioning and that is the sound you hear?
 

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Discussion Starter #4
Well I will add that the front wheel hub bearings are rough on at least one side for about a year now, but there is no gross bearing failure for sure.

ADDING. The sound was not in my face when I opened the hood/ so it seems like it's down low in the engine compartment. THE NOISE OCCURS WHEN THE CAR IS OFF and ON... I could hear the noise bouncing off the wall of the wendy's drivethru... So to be clear the sound is so loud that it initially got my attention when walking away from the vehicle to go in the drugstore...

WHAT IN THE H#(( is even under the hood that is mechanized and powered by electricity alone..?!?!?!

ABS light is the anti-lock brake system, not the airbag. It sounds like your wheel sensor is triggering something with the ABS, so I would start there. Not sure about the noise, maybe someone else can chime in
 

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Discussion Starter #7
Yea I am guessing the ABS control module is malfunctioning based on your help and some other reads. Apparently they will run once the key is removed and kill the battery too. The bad news is that it looks like it's a 300.00-$450.00 part. The good news is that it looks like I can pull the fuse and be done with it..

Repair-wise I am guessing their would be a failed or STUCK relay in there which may be replaceable with a soldering gun. I'll take a look tomorrow and give it the old BANG-IT-WITH-A-HAMMER test to see if it frees up..:confused::confused::confused::D

Not in the cabin, in the frame under the truck.
 

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Discussion Starter #8
ALSO - I am also not going to discount that there may be no issue at all with the ABS Module as something has to initiate it right...? Which I am guessing COULD BE a failed wheel sensor or whatever tells it to GO.. But still, the running AFTER the key is removed would go back to the module itself... Just BLAHH...
 

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It would be the ABS box that beach is talking about.
And yes, it does have relays.
They are also known to have cold solder joints on the circuit board.
And your research is correct, you can pull the ABS fuse and disable the system.
 

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Discussion Starter #11
Thx there is some good info there indeed. I replaced a front driver side hub 5 years ago with a 1A-Auto hub I got for well under 100 bux. My suspicion is that its the same driver side hub that is failing based on what I spent on it. However, my ears are failing too much near 50 years old or its the passenger hub & My "feel" for which side it is seems diminished as well. Is it me or does that driver side hub take more wear due to the weight of the driver..?

I'm getting leery to fix something that ain't broke... I was going to buy a cheap set of 2 and just do em both, but the link in that thread about the cheap Chinese steel scared me off now and perhaps I should just spend double and get one, replace the driver again, and then just move the current driver to the passenger if it is indeed the other one failing this time... Funny, in the 1980's Japanese steel was the problem because they did not have the iron ore resources to make good steel. I guess Corporate America is too cheap to spring for the nickel at the Chinese plants so oxidization is the issue huh..?

I'm just inclined to suspect the control module with what I have so far...

If your bearings are starting to go out, it may be just out enough for the ABS to notice a problem. Mine would engage every time I stopped. Just fixed mine a month ago. There is some good information to testing the sensors at that thread: https://www.gmtruckclub.com/forum/threads/yukon-xl-abs-is-overeager-after-speed-sensor-replacement.1467758/
 

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Discussion Starter #12
Where I am now is I woke up this morning and hooked the battery back up and away to noise went back to business. So its just doing its think like crazy without even a key in the ignition... I took the kids to school, got back 20 mins later, located the ABS fuse in the box under the hood and pulled it, the noise immediately stopped...

Here's a couple of pretty good vids I found later last night on actual solder repairs to the unit with both variants. They are pretty good.



I would just leave the fuse out and be done with it, but the ABS system works very well on this vehicle so it would be a shame not to use it. I've triggered it TWICE in my time with this car and both times very appropriate.

What I would like to know is can the vehicle be driven with the control module DETACHED (While I fix it) from the ABS Unit/ mechanical portion..? Or will things start popping out...?
 

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Discussion Starter #14
Well I got in the car yesterday later on after pulling that fuse and it's quite a light and bell show of naggs and warnings.. Something will have to be done no doubt... I MAY need that rebuilt one... Heating up solder on those multi-layer boards is not always gravy and caviar... It DON'T :confused::oops:always work out the way we want...

You can rebuild the ABS control module too and it is cheaper ...here is the link

https://circuitboardmedics.com/kelsey-hayes-325-abs-module-repair-chevy/
 

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2004 Tahoe Z-71 175K miles

So I get in the car tonight to run an errand and the ABS light is on under the tach. I THINK that's airbag not sure tho... When I get out there is a noise coming from behind the driver front tire THAT SOUNDS LIKE a small electric motor running with bad bearings, or a small water pump run dry... The abs light is the only thing new going on and directly coincides time-wise. I had to disconnect the battery just now as whatever is running under there would obviously drain it overnight...

I did pop the hood real quick but nothing jumped out at me. The sound is louder by the driver front tire that when listening from the top of the engine compartment...

Anyone...?
There are two places that rebuild the modals, They sent me a rebulit one for 115.00 , the dealer wanted 1150.00 still works like a champ going on 8 years now
 

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The first thing that should be done when you get an ABS light is to check the diagnostic codes to see what caused the light. You need a scanner that can read ABS codes. That will tell you whether there is a problem with the module, the sensor or something else. Remember codes don't tell you what is wrong only where to look. For each code there is a diagnostic procedure that should be followed to isolate the thing that has failed. Hubs are a key item when it comes to the sensors since they are either part of the hub or plugged into the hub. Sensors on your model vehicle can also be a problem as they tend to corrode where they plug into the hub and may require some cleaning of mating surfaces to provide a good signal again. This corrosion generated a recall on these vehicles 10 or more years ago and if you live in an area where salt is used to clear the roads the sensor mounts have to be cleaned every now and then to keep things working. As for the small electric motor sound that could be coming from the BPMV or if your vehicle has stability control it could come from the pre-charge pump that is turned on to build up hydraulic pressure when the steering indicates there may be a reason to activate stability control when there is no foot pressure on the brake pedal.
 
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