ABS Light On - Possible Causes?

[Ozz]

Greetings,
The ABS light on my 300A w/ 47,000 miles came on a couple of days ago and will not go off. I have checked tire pressure (one rear was down to 30 psi from the normal 38) and fluid level (level was fine - put high temp fluid in it 25k miles ago... no problems). After pumping up the tire, I unhooked the battery for an hour to reset any soft codes.
The light still comes on when I start the car and never goes off.
The only functional issue I noticed was that the ABS kicked in one time at low speed when I don't think there was any reason for it to.

Any ideas what may be wrong? Anything I can check in my driveway? If not, I have an appointment for the dealer to take a look on Monday.

[jgc61sr2002]

Probably a sensor. I think you have to get a scanner to get the code.

[Bluerauder]

Greetings,
The ABS light on my 300A w/ 47,000 miles came on a couple of days ago and will not go off. I have checked tire pressure (one rear was down to 30 psi from the normal 38) and fluid level (level was fine - put high temp fluid in it 25k miles ago... no problems). After pumping up the tire, I unhooked the battery for an hour to reset any soft codes.
The light still comes on when I start the car and never goes off.
The only functional issue I noticed was that the ABS kicked in one time at low speed when I don't think there was any reason for it to.

Any ideas what may be wrong? Anything I can check in my driveway? If not, I have an appointment for the dealer to take a look on Monday.
Not on the Marauder, but I had a similar problem with my '95 E150 Econoline conversion van. The ABS light would come on for no reason and stay on. However, when I shut it down everything would be OK for awhile. Then it would come on again. Seems to me that the problem was in the ABS light itself and that it was shorting out and staying staying lit. As I recall, there was nothing related to the braking system involved. Bad signal or bad wire. :dunno: Got rid of that van nearly 2 years ago so all the service papers are gone now. Good luck at getting to the source of the problem and getting it corrected.

[snowbird]

Maybe some crap/dirt in one or some of the sensors ? Maybe cleaning the four inner wheel area with pressurized water :rolleyes:

[rvaldez1]

The ABS runs two tests, a initial, and a rolling. You have a rolling problem so chances is a sensor or broken wire, also check the sensor at the diff.

[MENINBLK]

A cracked sensor would show/throw a code when moisture of any kind gets inside it.

When was the last time you drove through a puddle ?
Had the car washed in a car wash ?
Got caught in a heavy downpour ?

[Local Boy]

The diff. sensor is quite fragile...check there...ALOHA

[MENINBLK]

The diff. sensor is quite fragile...check there...ALOHA

Differential Sensor ???

We have 4 channel ABS, not 3 channel.
There is a sensor at each wheel.

[Ozz]

Drove through heavy rain the day before the light came on but it has been bone dry since then (3 days).

I will check the wiring... right before I noticed the light on I hopped the right rear wheel over a parking lot island (curb) as I pulled forward out of my parking place. Moving very slowly at the time but if something was loose, it could have jarred it looser..

Thanks!

[larryo340]

Probably a sensor. I think you have to get a scanner to get the code.
^^^^^^^^+1

[Ozz]

I have a Superchips tuner and I thought it would read codes... I tried it and nothing came up.

[MENINBLK]

I have a Superchips tuner and I thought it would read codes... I tried it and nothing came up.

You can't get ABS codes with an ECM scanner.
You need an ABS Scanner.

Try AutoZone, if you are near one, and ask if they can scan for ABS codes,
otherwise, you'll need to stop in and say hello to your dealer.

[Local Boy]

My bad (too much fun, not enough thought)...Thanks for the lesson...ALOHA

[Ozz]

It was the right front sensor that was bad. Since the dealership didn't have one in stock, they installed the complete hub assembly (which contains the sensor) for about $25 more than the sensor alone. With labor it was $380 to fix it.
$86/hr for shop labor is crazy money I think but when you need your car right away, I guess you have to pay it. :(

[03calitejas]

My ABS light has been on for some time and I now have my garage operational (finally). Jacked and supported the car w jackstands and crawled under the car (felt so good to be down there :) )and found that some road debris had cut the cable running to the front passenger side sensor. It was pretty mangled up so I had to cut out about 4 inches to repair it. There are two small wires (one black and one white) inside the cable jacket so it takes a bit of microsurgery with an exacto to clean them up and resolder. The cable originally ran around the backside of the A arm but since I had to cut some off I rerouted it along the front of it making sure that it doesn't bind when the wheels are turned lock to lock.

Not sure if the soldering would monkey with the sensor so I unplugged it first. (Its the rearmost of the 3 connectors on the inner fender liner.

Hope this helps someone else with the ABS light on

:beer:

[n00bkiller944]

$86/hr for shop labor is crazy money I think but when you need your car right away, I guess you have to pay it. :(

The benz dealer i work at charges 114.90 and we have the best price in the area, so I would say at 86 you got yourself a deal!