Diagnosing an Intermittant ABS Dash Light: Code C0035

MRRSM

Lifetime VIP Supporter
This Diagnostic Test for a Bad A/C ABS Wheel Hub Sensor can also be performed using a Hantek 1008C Oscilloscope + Laptop or Windows Tablet when reading the Graphed Square Wave Signal. The Vehicle must be Safely Jacked and Supported on Four Jack Stands:

 

Mooseman

Moderator
Good find. This one came up as a suggested video and is much more comprehensive without the need for a scope. Although he also shows with a scan tool with live data, it could be done with just a DVOM.

 

TollKeeper

Well-Known Member
Wow... How relevant..

I have been having unwanted ABS activation for about a month. It was only doing it when turning left, and my course of thinking was the right wheel speed sensor.

This morning I got a ABS light for C0036. Looks like I was wrong, its the left sensor/wiring. The one thing I dont have is a Oscilloscope, or even know how to use one. The bearing with sensor is cheap enough, I am going to start there, and hope its not the wiring.

Its just weird that it only happens when turning left, but not right.
 

Mooseman

Moderator
Maybe the wire or connector is getting flaky and when flexed a certain way, makes it manifest itself.
 

TollKeeper

Well-Known Member
This is on my GMT250 btw (Buick Rendezvous)..

That being said, the ABS wire comes down the the front of the lower control arm on top. I will order up the Wheel Bearings, and when replacing it, I will pull the cover off the wiring loom, and run a hand over it and see what I feel.

Im also getting a code U1301. Likely unrelated, but I have a feeling its what is causing my dash random resetting.
 
OP
OP
MRRSM

MRRSM

Lifetime VIP Supporter
@TollKeeper.... Regarding it happening during the turning events... I suspect that the Internal A/C Induction "Toothy" Reluctor Ring moves a little out of its orbit from the torque and stress on the Wheel Bearing and Housing (imparted from the Angular Momentum present while in the turns) just enough to disturb its pick up position with the nose of the ABS Sensor.

This Video "Kills Three Birds with One Stone" (Diagnosing the Class 2 Network U1064 U1300 U1301 Codes using a GM Tech 2 Scanner AND an Oscilloscope to visualize the 0-7 Volts DC Square Ware Pulse Width Modulation PWM Signals) on a Misbehaving Trailblazer. These Diagnostic Principles apply for all GM Class 2 Networks ...even if the Network Splice Comb Locations are to be found in different places inside your Buick Rendezvous:

 
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m.mcmillen

Gold Supporter
This is on my GMT250 btw (Buick Rendezvous)..

That being said, the ABS wire comes down the the front of the lower control arm on top. I will order up the Wheel Bearings, and when replacing it, I will pull the cover off the wiring loom, and run a hand over it and see what I feel.

Im also getting a code U1301. Likely unrelated, but I have a feeling its what is causing my dash random resetting.
The wire harness on those is very short and there isn’t much clearance between the wire and the CV axle. It is pretty common for the wire to fall slightly and the CV axle rub through the wiring. That could be your problem and it is rubbed though just enough to cause an intermittent problem.
 

TollKeeper

Well-Known Member
The wire harness on those is very short and there isn’t much clearance between the wire and the CV axle. It is pretty common for the wire to fall slightly and the CV axle rub through the wiring. That could be your problem and it is rubbed though just enough to cause an intermittent problem.
You were right, I tore into it this evening, and found that the wire had fallen on the CV axle, and that the dealer (repair done before I owned the truck) had replaced the wheel bearing, and routed the wire in front of the bracket, instead of behind it, leaving the wire and its sheath to rub on the CV axle. Got it routed correctly, and no ABS lights on my test drive, hope it lasts for a minute. Although the bearing is cheap, money is tight right now.
 
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