I am working on an ABS issue and especially would be interested in what our Pro's think. I have had the on again off again ABS warning. It has cycled, in general about every 1-2 drive cycles. ABS system operates normally when the light is out - at least it seems to operate properly on slick surfaces.

I have access to a very capable professional scanner and have scanned the system a number of times. Even with the ABS light on, I have not found any stored/pending or historical trouble codes. The only hard info I have is from the datastream. Before replacing the sensors with OEM parts the LF sensor would read 0.0 MPH both stationary and rolling, the RF would indicate .44 MPH stationary and rolling and the rears were indicating .44 MPH stationary, and gave accurate rolling info. So, at least for my scanner, .44 MPH appears to the default for stationary.

After OEM sensor replacement, I have picked up normal ops from the RF sensor, but still have 0.0 MPH in all regimes from the LF. I have not yet jumped into the troublshooting manual but am about to. Intuitively I would suspect a wiring/power/ground type of problem - I have done a cursory inspection of the LF wiring in the wheel well - but I was wondering if experience points any of our Professionals in any particular direction on the issue. I have no other noted electrical issues with the vehicle i.e. the flickering lights/instruments.

Thanks for any input.

 

There was a HUGE vendor issue with the wheel speed sensors on those. I've seen all 4 go bad within a week of each other before. Replaced some of them a day later after putting a new one on. It was a joke.

 

Absolutely Agreed.....

If you have the time and Patience...swap the sensor from R/F to L/F and see if your scan readings follow the change.....If they do....Get another sensor..If not ...Suspect wiring issues, or Possibly..(But much less likely) a bad tonering...

 

Ok Gentlemen,

Thanks for the thoughts. I do have time such that I could swap the sensors. And I have a "parts guy" that could put a new bearing/hub in my hand to rule out the tone ring issue - but I agree that is probably unlikely. I will certainly let you all know what I find.

 

Try a 30" red 4 gauge cable from the battery post to the post on the back of the fuse box. I had ABS issues, a new ABS computer didn't resolve it. I also had flickering lights, motor stall, radio static/on/off issues. $5 and 20 minutes worth of your time. There's some pictures in that post by razy "flickering" with 7 pages of response.

 

But....There is not a scan display with an obviously "Wrong Wheel speed" while the symptoms are occurring....

Loss of battery voltage will not affect a speed sensors ability to function, since they generate their own signal.

 

Thanks Joey for weighing in. I will keep that fix in mind if I deteriorate further into the flickering lights etc. For now I strictly have an ABS light.

I have not yet continued to sleuth the problem other than to pull out the troubleshooting manual. It does address a 0 MPH reading when both stationary and moving and points to the tone ring as a likely problem. I intend to get a replacement hub - they come with the speed sensor installed - and plug it in, and re-scan to see if there is any change (i.e. .44 MPH parked) before I pull and replace the bearing/hub.

I have noticed a change with the new OEM sensors in - the ABS does not pass the BITE test on initial key on, hence the ABS light comes on and stays. Before, I would often begin a new drive cycle with the light out and then have it come on at some later point.

A bit of a head scratcher. But, I do have time, and a lift, and air tools and a good scanner to work with. Heck and al Y'all too!

 

Just an update:

spent a while with the car the other day. Followed the steps in the troubleshooting guide. They basically detail how to test for proper voltage, ground, continuity etc. at the wheel speed sensor connector. Those tests revealed nothing out of the ordinary. At one point in the test we were directed to disconnect the connector at the ABS module to run some tests. We then, of course re-connected it. Still nothing out of the ordinary. When we were finished, a final scan still showed freeze frame data of 0 MPH on the left front. I went ahead and ran the command to "clear all DTC's" and called it a day - keep in mind there have never been any stored codes for ABS.

That was last Friday. The ABS light has remained off (comes on during power up of course) through many drive cycles now at varying speed. Go figure. Perhaps the "re-rack" of the module? I'll take it.

 

Just getting up to date with some of the threads on the Pacifica ABS light staying on. I have the Left Front Sensor Circuit Failure code. I changed the sensor, the light stays on. Thought it might have been a tone ring issue so changed the hub/bearing/tone ring assy. But the light stays on. I tried with 3 different scan tools to clear the code with no luck. Even the Chrysler scanner doesn't clear the code.

Sounds like some of you were having the same issue. Any tips or suggestions where to check next?