ABS Problems - 2006 Dodge Grand Caravan

Yep, that's exactly what I would do. GA

If the ABS is not getting a signal from the left rear wheel, I don't see how replacing the bearing could possibly help. Sounds like you just got ripped off.

I changed the sensor and sanded all the rust off the fins. The rust had scraped the sensor pretty bad, probably didn't HAVE to change it but I was there and it showed visible damage.

Now it (sanding the rust off the fins) is a maintenance item, I do it every spring and fall when I take everything off to check the brakes.

Thats how I fixed this problem. YMMD.

I got some wiring diagrams from Dodge. The sensors seem to be all the same ohm readings, I am going to scope the incoming signal from the sensors at the control module. Since there seems to be a diode in the sensor I should get a square pulse going into the control ???

I don't think that is a diode. I believe you should see an A/C signal measured in millivolts.

Thanks Bob;

If you ohm it with lead one way you get resistance then reverse the leads you get an open with the meter on diode test. This is true with all the sensors. Too bad someone didn't know exactly what the pickup is ?? Is it a coil or Hall effect switch??

Thanks for your support

I believe they call the sensor a magneto resistance bridge.

Have checked a 2008 Caravan ABS wheel sensors, I presume they have internal electronics, you will see an open circuit ( maybe 20-30 mega ohm) testing with an ohm meter. Ohm reading will not be a conclusive test with this type of sensor. The following test worked for me. Leave sensors connected to vehicle, connect digital multi-meter set on DC volts to the 2 wires going to sensor, turn ignition to on position, you should see 10 -12 volts from ABS computer, now set digital meter to frequency mode, rotate the wheel in question and watch for frequency reading, on a good sensor I see 40 - 50 Hz when turning wheel by hand. If reading stays at zero then you have bad sensor. If you don't see voltage from computer check wiring, connectors etc.

Well I guess the problem is finally fixed. The ODBII reader at the Dealer was saying Left Rear but it turned out to be the Left front. One of the wires was corroded where it was crimped in the connector. The resistance was enough to kill the pulse. The pulse is detected as a change in current (Current loop) as the tone wheel passes the pickup. Thanks everyone for all the suggestions. I am glad this one is over.

Thanks for the heads up.

a change in current (Current loop) as the tone wheel passes the pickup.

Does the same thing happen as you pass a van?

Glad it worked out well for you. Thanks for the update.

Thanks Bob, I am a little slow on that one. Too bad they wouldn't get there act together and sync the ODB reader messages with the real world.....

Like the 38 PIN numbers that I need to remember for the 38 different cards with magnetic strips on them? If all of these high security facilities require one to have a driver's licence to work there, why do they each need to issue you another card with your picture on it and another magnetic strip?