ABS light and brake light coming on, going off and then coming on again.

NJaloha

Member
:
2003 P5
So my abs and brake light have been coming on on my dash. Along with these lights coming on, when I apply the brake, I feel a pumping like the abs is going off. After I pump the brakes a few times, the abs pumping sensation stops and the abs/brake lights come on on the dash and remain that way until I turn the car off. When I start the car up again, the abs/brake lights are off and when I step on the brakes, the same thing happens all over again.

I think it must be that the abs cable is loose or maybe it is not firing correctly. Any ideas?
 
For the ABS light, sensor in the back may need replaced. It can get knocked around with pot holes and stuff.

E-brake light usually only comes on and stays on for a couple reasons, ebrake is pulled up a little or has a bad cable, low brake fluid due to a leak or worn pads (which may be you're pulsating feeling when applying the brakes) bad tie downs, or a ceased caliper.
 
I can verify that the brake light doesn not come on for the rear brakes on non abs so I doubt it would for the abs...just sayin. But take it to autozone and see what code its throwing. But plan on doing a brake job
 
If the parking brake light comes on with the ABS light it means one of the rear sensors is not producing a strong enough signal or is open/short circuited (see the footnote on page 04033 of the service manual). You can figure out which one is causing the problem by getting the ABS computer to blink the code out to you (see page 04023 of the service manual).

Once you know which sensor is causing the problem, you'll have to remove some of the rear trim to get to the sensor's connector (the large piece of plastic right by the rear door). Then you'll unplug the connector and test the resistance across the sensor, if it's not in the proper range (1.3 to 1.7 kOhm) then the sensor is defective. If it is in the proper range then the problem could simply be that the sensor is covered in dirt which is affecting it's output voltage.

To clean it you'll need to remove the caliper and rotor and spray the sensor and the toothed ring with brake cleaner until it's all nice and shiny. I had that happen to me a few years ago. After I cleaned the sensor it lasted a little over a year before finally dying for real.
 
Wow. Maybe it's worth just replacing the entire thing now if it's going to go anyway. Also, important to note that my ebrake has ZERO braking tension to it, but it's been that way for about a year now.
 
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