Jon Report post Posted May 26, 2021 Picked up a high mileage '04 Limited 4WD with the 3.0 for my son turning 16 soon. We've done quite a bit to get it ready for the road, but now having a problem diagnosing the brake light and ABS light. They come on randomly. Sometimes when starting to drive, there will be no lights on, then after a few minutes of driving the brake light and ABS light will turn on and stay on until the car is turned off again. Sometimes when it's started, it will have just the ABS light on, sometimes just the brake light, and sometimes both, and sometimes no lights. I have a scanner with ABS, and it shows no codes set for ABS. Fluid is full, and there are no leaks. Brakes seem to work fine, but I have not tested it hard while the lights are on. Where to start? Replace the brake level sensor maybe? Share this post Link to post Share on other sites
Knottynuts Report post Posted June 4, 2021 Most common cause is a faulty wheel speed sensor with an intermittent break within the wiring. ABS codes may only be stored during that drive cycle only so you would have to scan the vehicle when a fault occurs BEFORE turning the ignition off! Otherwise you would need to watch the live data for each wheel speed sensor and then you could see which one(s) is (are) dropping out. Share this post Link to post Share on other sites
