Anti-Lock Brake Light On

[Gary Sasinowski]

I have a 2000 Buick Lesabre 3.8 L. engine with 220xxx mi. and the anti-lock brake light is staying on when driving it. I have brakes so I’m not worried that way and am moving to SC from NC hopefully next month so I don’t have to worry about an inspection but I can’t figure out why the light’s on. I checked the anti-lock sensor connections at the bearing hubs on both sides and they are connected and no wires are cut (I’ve had that happen after changing a bearing hub in the past). I’ve checked the anti-lock brake solenoid and didn’t see anything obviously wrong. Is there any way to test the system with a scanner of some type? The OBDII scanners/readers I’m familiar with don’t check anti-lock brake systems but is there a type that does? Thanks for the responses in advance.

Topic

[Greg]

Yes there are scan tools that read abs codes. It sounds like you may have a bearing that is failing

[Gary Sasinowski]

Thanks for the info. I am unfamiliar with how that type of scan tool works; would it verify a the bearing failure or do I troubleshoot that like a normal bearing hub issue?

[zero]

In many applications of that era GM used a simple 2 wire system for the ABS sensors, as opposed to the bonded one piece 2 wire system that most other manufacturers use. It is extremely common for one of these wires to brake, the good news is it’s both easy to find and easy to fix. If you can, get the code pulled first, this will identify the offender. Jack up the car, pull the wheel off and proceed to pull back the plastic sheathing to inspect the wires. The breaks tend to happen anywhere there is movement, so if you make it all the way from the sensor to the subframe without finding a broken wire, it may be another issue. If you find a broken wire, repair it.

With the ABS sensor wiring disconnected, you can also use a DVOM set on AC volts to check the sensor itself. *Please note that this is not the most accurate test, but more a proof of function test, even a momentary signal loss might set and ABS code. A standard DVOM does not have the resolution to pick up fine variations or momentary signal loss.* By spinning the wheel or hub the sensor will generate a voltage reading, the number doesn’t matter, you’re just looking for a reading. The sensor on your car is integral to the hub assembly and has a pigtail going to the connector, Checking for output will confirm the unservicable parts are functioning.

I’ve repaired more GM ABS wiring than I’ve replaced sensors on everything else combined. If these test fail to yield results, more thorough diagnosis is required.

[Gary Sasinowski]

Thanks for the info. It may take a few days to check this out due to a heavy work schedule but as soon as I can, I’ll double check the wiring and try the spin test with VOM.

[Kevin]

Could be anything, abs module, a computer, and sensors. If it isn’t bearings, I wouldn’t worry about it personally. I drove a Concorde that had an abs light on never had any issues braking. The only time ABS is nice is in snow.

[Author]

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