How do you troubleshoot an ABS light on a 1997 Cadillac Deville?

Answer 1

This is a start but beyond this get your wallet out. The ABS and Traction Control are an integrated unit, ie: either could be at fault. First place to look is the wheel sensors, take one wheel off at a time and in behind on the back side of the hub assembly you will see an electrical connector with two wires going into it. Unsnap the connector and measure the resistance across the (wheel side) of the plug with your digital meter - set meter to ohms - mine were about 1.110 to 1.052 on the 2K ohms scale. What the actual reading should be I dont know but you can get a good idea if one is bad by comparing the measurements from all four wheels. Obviously a reading on one well above or below the others is a good indication of a bad sensor. The other check to do on each sensor is to check that the sensor is outputting. Connect your leads across the (wheel side) of the plug again and set your meter to AC volts on the lowest scale. Now put your wheel back on with a couple of nuts hand tight and spin the wheel while watching the meter. Mine showed about 0.40 volts turning as fast as I could - the voltage will vary the faster you turn. If you have no AC volts on one then take the brake caliper off and the rotor and inspect / clean the sensor and pulse mechanism from the inside & try again. Next - *switch on your ignition* & connect your meter across the (CAR SIDE) of the plug and switch to DC volts on say the 20 volt range - the reading on mine was about 4.7 volts and varied about 0.2 between all readings. (DO NOT SHORT OUT THESE BY ACCIDENT - GO SLOW USE EXTREME CARE) Again I do not know the actual spec but a reading on one greatly different from the others is a good indicator that something is wrong with the ABS module itself or the wiring leading back to it. Follow each line and check all plugs found. On the rear wheels the right and left sensors converge into a four wire plug fastned to a cross member about mid point. You can actually do all your checks here for the rear wheels without taking the wheels off if you want. The front is impossible to follow any distance.

Note that the plugs Cadilac uses for this system is absolutely pathetic considering the extreme harshness of the environment being right at the wheels and inches from the ground. Stones sticks or ice could rip them right off the car and they are watertight plugs not waterproof. WHAT A CRUEL JOKE! GM Engineers are morons. Instal an expensive safety system to insure it will never work when you need it most - wet & snowing. In any case this is as far as I got, all my readings were similar and therefore my problem is (not likely) to be a sensor. I'll add to this as I (learn more) & work back toward the actual system.