ABS Warning Light

[kdannyk]

Just wondering if any one would know if a bad Wheel Hub would cause the ABS light to turn on? I know my wheel hub is bad and the bearings are shot just not sure if that would cause ABS light to turn on.

 

[HARDTRAILZ]

Yes it would.

 

[IllogicTC]

If you're wondering about the specifics of why, it's in the basic operation. There is a sensor, and a wheel which the sensor detects as "on/off" pulses. Imagine holding a light up to a fan, and turning it by hand -- there is a definite "ON" pulse when the light shines through, and an "OFF" when the blade covers it, and the sensor is similar in concept.

The sensor remains on the stationary side of the hub, and the wheel turns with the moving side of the hub, generating on/off pulses that show the speed of the wheel. Now imagine when a hub is failing and loosening up. That wheel would start coming out of alignment with the sensor, and therefore the sensor may only detect some pulses, or none at all. Meanwhile, we can assume the other speed sensors are still sending out proper signals. The EBCM sees this, and sees that you're not pushing the brake but the wheel appears to be going much slower/stopped compared to the others, and the system determines to turn on the ABS lamp.

 

[GMDUDE2003]

Hmmm. I changed my hubs last summer. I'm having this problem as we speak. I'm gonna clean the the connectors and check them for tightness. Sometimes I get a small pulsing at 37-40 mph and at coming to a complete stop. It will go away and come back. Very strange, wish my ODB II would catch ABS codes.

 

[GMDUDE2003]

I've finally read the codes for the ABS.

C0035
C0040
C0045
C0050
C0244
C0245
C0287

It appears that what I read on these its affecting all 4 wheels (first 4 codes) wheel speed circuit malfunction.
C0244 I don't know, wasn't listed. C0245 Wheel speed sensor frequency error. C0287 Delivered torque circuit. Not seeing why changing the front 2 hub assemblies would affect all 4 wheels. Maybe the last couple codes could help decipher ? Any ideas gents ?

 

[IllogicTC]

With traction control, C0244 is part of the diagnostic code set relating to the six valves in the EBCM

Without traction control, all I can find is it being listed as part of a group of codes relating to wheel speed sensors, however this is in a group of 14 codes and there definitely isn't that many sensors.

Also, C0287:
DTC C0287, P1644, or P1689

Circuit Description
The EBCM supplies 5 VDC to the powertrain control module (PCM) on the delivered torque signal circuit. The PCM toggles this voltage to ground in order to create the delivered torque signal at the EBCM. A signal with a frequency of 128 Hz 5 percent and a duty cycle of 25 - 95 percent is a valid delivered torque signal. The percentage of duty cycle is proportionate to the percentage of delivered torque.

DTC Descriptors
This diagnostic procedure supports the following DTCs:

• DTC C0267 Delivered Torque Signal Malfunction
• DTC P1689 Traction Control Delivered Torque Output Circuit

Conditions for Running the DTC

• The ignition is ON.
• The engine is running at a speed greater than 450 RPM for 1 second.

Conditions for Setting the DTC

C0287
The electronic brake control module (EBCM) receives an invalid delivered torque signal for 300 milliseconds.

P1689
The powertrain control module (PCM) detects the delivered torque signal voltage as being less than 4.75 volts or greater than 5.25 volts .

Is it safe to assume you have traction control? I'm fairly certain C0287 only deals with traction-equipped vehicles.

You may have a look at the EBCM pigtail and the connector on the unit itself, my first thought would be that there is advanced corrosion or something. Faulty connection to the speed sensors, to the PCM for delivered torque signal, and possible faulty power/ground causing solenoid valve malfunctions. If not this, my next thought would be the EBCM itself is done for. Considering its location, a thorough check for tight electrical connections without corrosion is a must.

 

[GMDUDE2003]

I do have traction control. Im just gonna have to go through the whole system to find the problem i suppose. I would wonder if the ebcm was shot would it throw a specific code for it dying or would every code related be thrown ? Sadly i do not have direct access to a better scanner then the one I have.

 

[IllogicTC]

I do have traction control. Im just gonna have to go through the whole system to find the problem i suppose. I would wonder if the ebcm was shot would it throw a specific code for it dying or would every code related be thrown ? Sadly i do not have direct access to a better scanner then the one I have.

Being able to get Chassis codes is already a couple steps up from the basic "here's your number" scanners that only show P-codes (especially the ones that don't give a description!)

Start with a full examination of the wiring, harness, and connector to the EBCM.

 

[GMDUDE2003]

I had to pull the ABS fuse for it was starting to lock up the tires on the highway on the way home. From first inspection, the fuse looks to be fine lol, and was properly secure also. Now, my next step will be to clean the ground under the drivers door. I have a friend who has a decent scanner, but is not as close as would be helpful. Where exactly is this EBCM located so after I clean the ground I can eyeball and inspect it.

 

[IllogicTC]

Pretty sure it's mounted on the inside of the driver's side frame rail, somewhere between the A pillar and B pillar area.