sighhhhhh. GM Electrical problem need help

[motionclone]

I made the poor decision to once again try driving a GM product and now im paying for it.

2015 GMC Denali 1500, 110,000miles. ABS/STABILI trac light and warnings came on and went off 257 times the other day while on a 1.5 hour mission. Each warning gave rapid, loud very distracting tones and braking was sketchy.

-Happened while driving slow and bumpy, come to stop then take off and the abs light would come on.

Code reader said c0035 which is an abs fault on the driver side front. Erase codes they just came back as soon as i stop and take off again or go over bump.

So I buy an ABS sensor from Napa.

Put it in that night, erase codes and code comes right back on, same code same warning. So i go through and clean the abs connector real good with elec cleaner, still no go. So i clean all the connectors i see that the abs signal wire may pass through, still no go ABS fault.

Plug in the old abs wire, clear codes. all is fine...wtf

So i return the abs sensor to NAPA and told them i think its defective.

Drive 500 miles or so no issues.

Today the same thing happened. So this time i bought an abs from Advance. Same exact issue. Replaced the sensor, erased codes but code comes right back same code c0035.

Put the old one back in, cleared the codes and just took it for 10 minute hell ride and all seems fine.

What causes this?

 

[trial and error]

It could very likely be
a short somewhere in the harness I experienced a similar scenario in a 07 nitro and it took several shops and lots of $ in diag fees to find the issue Not saying this is it but that my .02cents

 

[motionclone]

It could very likely be
a short somewhere in the harness I experienced a similar scenario in a 07 nitro and it took several shops and lots of $ in diag fees to find the issue Not saying this is it but that my .02cents

probably what it is but how does a new sensor not fix the problem but putting the old sensor in fix it?

 

[William1]

I had similar issues in another brand. It was low voltage due to a dirty plg at the ABS computer from a wheel sensor. These things all run a low voltage and milliamps, so it does ot take much for corrosion to cause a fault. Give me a 1960's engine with a single wire from the distributor and three from the alternator....

 

[Fordtech86]

Is the hub loose?

 

[trial and error]

Shorts in wiring are a funny thing, and I don't think putting the old sensor in "fixed it" as you already stated you tried that once then the problem came back so u tried the advance auto sensor

 

[motionclone]

Shorts in wiring are a funny thing, and I don't think putting the old sensor in "fixed it" as you already stated you tried that once then the problem came back so u tried the advance auto sensor

Yeah both a napa and an advance auto sensor seemed tonot work indicating to me the problem is not the sensor but wiring up stream. but putting the old sensor in stopped further fault codes or abs light from coming on....for a while anyway

 

[motionclone]

Is the hub loose?

seems tight and no noises. otherwise i would guess that to be the original issue if not the sensor itself but my symptoms are weird. Plugging the old sensor back in made the fault codes stop. 2 New sensors from 2 places cause a c0035 code to reoccur.

This all while on jackstands, no wheel movement or driving.

 

[motionclone]

I had similar issues in another brand. It was low voltage due to a dirty plg at the ABS computer from a wheel sensor. These things all run a low voltage and milliamps, so it does ot take much for corrosion to cause a fault. Give me a 1960's engine with a single wire from the distributor and three from the alternator....

ill have to trace that wire further and find where it plugs into abs computer...if i dont sell the thing first

 

[ve9aa]

Ohm out the harness for that sensor - END TO END (audio mode on your multimeter is easiest).

Jiggle wires.

Listen to your meter.

Find the "open" (or short")

That's where I'd start.

Dang intermittent problems are the WORST!

 

[motionclone]

Ohm out the harness for that sensor - END TO END (audio mode on your multimeter is easiest).

Jiggle wires.

Listen to your meter.

Find the "open" (or short")

That's where I'd start.

Dang intermittent problems are the WORST!

i think thats the next step. i just need to locate the other end of those wires for the sensor. I DID try the jiggle method on every wire and harness i could see that i thought would contain the sensor wires and nothing i did triggered a fault again.

 

[DaveFromMi]

I had the same problem on my 2016 Chevy Colorado.
The ABS/Stabilitrac lights came up intermittently then permanent.
Here is what happened.
The high mount stop lamp reflector seal (foam melt at factory) developed a water leak.
The water came in through the seal, travelled right and left, down both C pillars, forward downhill through the sill/floor pan metal finally pooling up under the front seat carpets. On flat ground, the water flow path is all downhill.
At the time of the warning lights, I noticed a musty smell. Since I have WeatherTec floor liners, I had no idea my carpet was soaked.
Under the carpet, the power wire that feeds both ABS and Stabilitrac had corroded and eventually had an open circuit.
Mending the wire fixed the electrical issues. I used an electric heater, dehumidifier, and a Shop VAC to dry out the floors and carpet over a period of 2 days. I sprayed some Lysol under the carpet and Fabreeze in top of the carpet. It got rid of the smell.
The stop lamp gasket was replaced with a closed cell foam seal. Since I heard that the XM antenna mount seal could have the same problem, I replaced that seal as well.
Some cheap factory seal caused a major problem.

 

[GeoHorn]

Overhead Rear stop light/cargo-lights leaking water into the cab is a common PU Truck issue.

I had a similar electrical ghost problem unrelated to that light. It was where the wiring harness passed thru the firewall beside the brake master cylinder. The grommet that was intended to protect he harness had a defect/spit that allowed the sharp edge of the hole thru-which the harness passed… had cut thru the insulation of the wires…and occasionally a bump in the road or vibration would create a short between two/several/sets of wires …which gave a myriad of goofy results.

Pulling/manipulating the harness eventually led to the discovery.

 

[Torinodan]

My XM antenna leaked on mine (2015) and was causing problems in my steering wheel controls. Dealer fixed the seal, still have some ghost issues from time to time. I had water leaking on my lap during rain and car washes.

 

[motionclone]

I had the same problem on my 2016 Chevy Colorado.
The ABS/Stabilitrac lights came up intermittently then permanent.
Here is what happened.
The high mount stop lamp reflector seal (foam melt at factory) developed a water leak.
The water came in through the seal, travelled right and left, down both C pillars, forward downhill through the sill/floor pan metal finally pooling up under the front seat carpets. On flat ground, the water flow path is all downhill.
At the time of the warning lights, I noticed a musty smell. Since I have WeatherTec floor liners, I had no idea my carpet was soaked.
Under the carpet, the power wire that feeds both ABS and Stabilitrac had corroded and eventually had an open circuit.
Mending the wire fixed the electrical issues. I used an electric heater, dehumidifier, and a Shop VAC to dry out the floors and carpet over a period of 2 days. I sprayed some Lysol under the carpet and Fabreeze in top of the carpet. It got rid of the smell.
The stop lamp gasket was replaced with a closed cell foam seal. Since I heard that the XM antenna mount seal could have the same problem, I replaced that seal as well.
Some cheap factory seal caused a major problem.

Where you able to get a code and what was it during your issue? Sure sounds like i got a wire problem somewhere similar to yours

 

[RBsingl]

I went through this years ago with a 2001 GMC 2500HD, the procedure for running down the issue is in the service manual. But a quick google search brought that procedure up in this thread which you may find helpful: https://www.gm-trucks.com/forums/topic/150537-c0035-fix/page/2/

One of the important diagnostic checks is you can check if the tone ring and pickup combo are generating a signal. Using a scope to look at the output is far more definitive but a meter (set to AC) will read the output from the wheel speed sensor while spinning the wheel to show basic function but it won't show if it is generating steady pulses of roughly the same peak value but at increasing frequency as the wheel sis spun faster.

Rodger

 

[will721]

One of the important diagnostic checks is you can check if the tone ring and pickup combo are generating a signal.

100% this^

Mind you it's been a long time since I worked on cars professionally, 13 years or so now. But in my experience nine times out of ten an abs code for wheel speed signal isn't the sensor unless it has an external pickup ring on a cv axle. If the tone ring is internal to the hub assembly its almost always an early warning to a failing hub assembly. Of course I can't say for sure without tests but that is my experience.

 

[DaveFromMi]

Where you able to get a code and what was it during your issue? Sure sounds like i got a wire problem somewhere similar to yours

I didn't use a code reader. ABS/Stabilitrac Failure appeared in the meter. It looked something like this.
Neither function worked and one or the other disabled the remote start function.

 

[William1]

Another thing that can do it is a bad brake light switch at the pedal. As well as the previously mention 3rd light issues. A lot of things can provide a poor signal/glitch and the ODB error code is not always an exact science.
What also sucks is going through all the connections and finally, no more error and you really do not know what of all the things you did was the actual fix.
Triple confirm too, battery voltage at the battery, a good 12.8 volts. Had another vehicle that had ABS issues. It was not driven often, the battery voltage was at 12.5 volts and the charging system decided that was 'good enuf'. Well, it wasn;t. Put the battery on charge and the ABS light went out. Owner now has a trickle charge on it as it sits for weeks with the computer doing a parasitic drain.

 

[#40Fan]

My guess would be rust! Enough has built up that a new sensor won't sit close enough to the reluctor ring, but the old one will. This could be because the aftermarket is slightly shorter than OEM, different magnet, etc.