JG928S4

1988 S4

Brake Pad sensor light comes on. After car shutdown warning not displayed until 5 minutes or so of driving then warning comes on again. Check all pads, lots of life left upon eyeball inspection. I check all wiring on/around calipers and it looks good. Where to next?

JG

Nicole

Similar porob here, but always comes on when car is started and brake is tapped for the first time. Initially, it was intermittent, new sensors in the rear fixed it. Then we had to remove and replace the rear pads again, and since then I get the warning every time. New sensors made no difference.

What's the procedure to narrow it down to the correct side and front or rear? How to narrow it down to where the fault is located? Is it something an electrically challenged person can troubleshoot?

Andre Roodnat

The best way is to get the wheels off. Start with the one who you think is most suspicious, like where blocks were replaced or other work was done. On the caliper you’ll see the red wires, which go through black small tubing. Follow this tubing. These are fitted with connectors into a cylindrical black connector block. You can pop the black cover open by twisting a screwdriver under the clip in the middle (closing is best done with adjustable-joint pliers, as they close up quite tightly). Carefully pull the connector out by wiggling. Measure with a multimeter if the sensor is ok. It should be a closed circuit. Also check the connectors (the male as the female) for corrosion. Apply cleaner if necessary. If OK, reassemble. Check if the black tubing with the 2 leads is in place everywhere. It should be kept in place with a couple of clips and clipped in the caliper. If it’s not correctly routed, it can touch moving parts and wear through (this happened to mine).
If all four turn out ok, the second point to measure is the connectors in the spare wheel well (for the rears) and on both shock towers under the hood. They are the same as the connectors at the wheel. There are 3 connectors in the connector housing. 1 for RDK (if present), 1 for pad sensors and 1 for ABS. They are all 3 different. The RDK plug is the same as the one at the wheel. Measure through both leads and measure for disconnections. From there I can’t give you any further advise, cause I’ve never been there. But the culprit is most likely to be found at the wheels.

Intermittent warnings are most likely caused by worn leads. I had the same.

JG928S4

thanks, I will give that a shot.

Bill Ball

Nicole:

It is possible the new sensors were not connected correctly. The plastic block into which it connects has 3 holes. One is for the ABS sensor, a second is for the brake pad wear sensor and the 3rd is unused unless you have RDK. Your sensor maybe inserted into the unused hole. I did this recently on my car.

Otherwise troubleshooting would involve testing each sensor for continuity.

Remind me when we do your timing belt next month and we will check this.