The yellow Anti-lock Brake light is turned on by the ABS computer when a problem is detected. The fact that it does not go off means it's not an intermittent problem. Permanent problems are easier to diagnose. Common problems are low fluid level in the master cylinder, a blown brake light fuse, often caused by a trailer wiring problem, and defective wheel speed sensors. Your mechanic will connect a hand-held computer to the system to read the diagnostic fault codes. The codes will lead him to the circuit or part of the system with the problem.
If you can provide other clues, it might speed the diagnosis and save you some money. Helpful observations include, 1) does the yellow light turn on as soon as the engine is started, and stay on? Electrical self-checks, fluid level, or pressure problems are detected. 2) Does the light turn on during the two-second system self-test, then turn off, but turns back on after driving a few hundred feet to a mile or more? Suspect a cracked tone ring by one of the wheels if the light stays on until you turn the ignition switch off and back on.
Other electrical problems include one bad section of the brake light switch and a stuck-on parking brake light switch.
The traction control is an add-on option to the ABS system. It can't work if the ABS system isn't working. That's why the second light is on.
Tuesday, April 7th, 2009 AT 7:31 AM