Under what conditions "BRAKE" light in dashboard can be related to malfunctioning ABS?

Question

On my Chevrolet Aveo 2007 I have had ABS light intermittently turning on and off for around a year. Besides the ABS light in dashboard, braking seemed to work normally until 2 weeks ago when ABS occasionally started to kick in when it should not have (i.e. pulsing pedal and increased braking distance). Then few days ago also the "BRAKE" light started to turn on intermittently in dashboard. I checked the brake fluid and it is ok. I also pulled the handbrake, but it did not have any impact on the BRAKE light in dashboard. I am now left wondering if there is another separate issue with BRAKEs or if it is related to the ABS issue.

Today as part of experiment I also removed ABS fuse. What I am seeing after removing it is that:

1. Both ABS and BRAKE lights are now constantly on; AND
2. Haven't noticed ABS kicking in anymore (because it is effectively disabled after I removed the fuse).

When I put back fuse, then again BRAKE and ABS light is only intermittently on.

My question is - If and How ABS system could have impact on BRAKE light in the dashboard?

Answer 1

Brake (at least on my old Ford system) is just the emergency brake. If I were to guess it's more than likely a separate, unrelated issue. I would look into the E brake sensor, see if the E brake is sticking and/or see if there's slack in the E brake line.

Did you find out which of the sensors/wiring harnesses is bad (ABS issue)?

Answer 2

Get your ABS system checked. If you want to start the procedure yourself:

1. Jack one corner of your car up and place it on a jackstand.
2. Remove the wheel.
3. Look for the electrical connector of that wheel and inspect it.
4. Disconnect it and perform an electrical test on it. First, measure the AC voltage the sensor produces when you are turning the wheel by hand (put the car in neutral with the parking brake on when doing the front, car in park with parking brake off when doing the rear. Always block a wheel with wheel chokes). Second, measure the resistance of the cable.
5. Do this to all 4 wheels. If everything checks out, the issue may be with the ABS controller.

Alternatively, an auto parts store may be able to read the ABS trouble codes from your ABS controller. If the light is on, the controller has something to say. :)

Answer 3

You have to check your abs controller for errors. If your lights are on when ABS or handbrake is NOT on, this would normally suggest that you have faults in the system and instead of trial and error, you can read what is wrong from the computer.

For example, removing the ABS fuse can make your system record an error (because ABS obviously won't function!) and cause ABS light to turn on permanently! Putting the fuse back, may or may not turn it off. Depends on the vehicle and type of problem.

Once I removed dashboard fuse and this caused airbag controller to record an error (because it couldn't reach dash board) and after I put back the dashboard fuse back, I had to reset the error from the computer.