Jump to content
Sign in to follow this  
Ferret II

Anti-lock Braking System - Traction Control

Recommended Posts

Hi.   Has anyone had success reading ABS codes?  Our scan tool, despite being fairly sophisticated, just can’t seem to communicate and retrieve ABS data.  We think the issue is related to diagnostic standardization being developed around the time the car was manufactured (’96 Mercury Mystique LS, MTX, 2.5L).  Any tips or ideas will be greatly appreciated.

 

Thanks!

Share this post


Link to post
Share on other sites

Hi.  Here's a little more info.  What’s happening is my Traction Control light sometimes comes on after driving awhile, and stays on.  Upon re-start, after the engine has cooled, it operates normally for awhile.

 

About a week ago, on a very rainy day, the TC light came on.  However, this time, a bit later in the drive, the ABS light started blinking in time with the TC light – i.e., when one would flash off the other would flash on.  As I drove this “light show” grew quite fast and somewhat random (though still following the one light on the other off pattern).  I didn’t notice if it was related to driving speed, but it didn’t appear at all related to braking.  This weekend, on a less rainy day, I drove the car and eventually the TC light came on, but the ABS light stayed off.

 

Also, the CEL came on during the “light show” drive, but when we read the engine data there was nothing new or surprising.  However, the issue is we can’t access any ABS data (this is through the OBII under-dash connector).  There’s a message “Trying to Communicate”, but nothing happens.  We have three scan tools, and all three read ABS/wheel speed/wheel sensor data on our Chevy GMC truck, but we cannot get any of the scan tools to retrieve any of this data on the Mystique. 

 

The three scan tools are:  Snap On MT 2500, Tech One, and Auto Enginuity.

 

The Mystique factory manual does call for a brake-out cable connected to a under hood connector utilizing a star tester, but we think that may be because the modern scan tools may not have been available in the mid-90s.  The GMC truck is a ’96, too, so it seems a Ford issue.

 

My tires are new and properly inflated; and at least the front brake pads are pretty new, and the brakes work fine.  The car has 60K miles, and so far the engine harness appears in great shape.  

 

Also, just to note, on my car when the TC button is pressed the light comes on and TC is off/disabled.  Press the button again and the light goes off, enabling TC.  However, currently, after the light spontaneously turns own depressing the TC button does nothing.

 

Any ideas about accessing data or otherwise troubleshooting would be greatly appreciated!

 

Thanks.

Share this post


Link to post
Share on other sites

I have the Auto Enginuity PC based scan tool and was able to read an ABS code on my 2000 SVT Contour.  The fault was a front wheelspeed sensor; replacing it fixed the issue.

 

I do have the "Ford Extended" option (whatever it's actually called) on my scantool, I doubt that it would read ABS without it.

Share this post


Link to post
Share on other sites

Thank you very much for the comments!  Both are very helpful.  We continue to troubleshoot and gather information, and I'll be posting an update soon.

Share this post


Link to post
Share on other sites

In the EVTM Ford manual on page 151-4, there’s a diagram of the engine bay showing an ABS Diagnostic Connector; it’s located at the inner, top front area of the wheel tower and numbered C-126. 

 

Just wondering if the following is correct:  If I hook up a ground to this connector it should flash ABS codes (in the case they exist), i.e., the ABS lamp would blink out a code inside the car.  If this is correct, does anyone have any other information about the procedure for this?  For example, should the car be running or ignition on; and should it be temporarily or continuously grounded?

 

I want to make sure I don’t ground something out! 

 

The reason I’m approaching it this way is I can’t get codes through the DLC connector using any of my scan tools.  The DLC looks to be an OBDII, but does not provide ABS data, which may be why the ABS Diagnostic Connector is under the hood.

 

Thanks!

Share this post


Link to post
Share on other sites

Hello.  The wheel speed sensors tested okay, and I’ve checked some wiring and grounds.  Still trying to rule out whatever I can before taking off components.

 

 

 

I’ve found a backup lamp switch issue, which is probably unrelated but I’d like rule it out.  The back-up light comes on briefly when I start to back up, then goes out.  If I barely hold the transmission in reverse, even lightly touching the shift knob, the backup light stays on, operating as it should.   I searched here and on various other forums, but found little info.

 

 

 

A pretty comprehensive search for the part has turned up no availability – OEM or aftermarket – of the backup lamp switch I need, which is for a pre-98 MTX (rod shifter).

 

 

 

Does anyone know if a very slight adjustment to the linkage could correct the backup light issue?   I’m guessing this might be a question Terry may be very familiar with!

 

 

 

Also, any suggestions for the easiest route to the ABS module wiring, so I can check the connections on the two wiring harnesses?

 

 

 

Thanks!

Share this post


Link to post
Share on other sites

Rod shift reverse light switch is unique to rod shift only. Do not try to adjust it out but remove it and check the screwed in 'pin' that operates it is OK and tight etc. A used switch maybe your only option...

Share this post


Link to post
Share on other sites

Thank you, Terry! 

 

I don’t know for sure when the rod shifter was changed to cable (I think 1998?), and am wondering if there’s any chance the backup lamp switch for the '98-99 Contour or Mystique 2.5L w. MTX might work, or be modifiable? 

 

We haven't taken out the backup lamp switch (it’s not very easy to take off, so hoping to have the part first); but from the outside it looks like the ’98-99 switch, which is available - I pasted a couple links to pictures here: 

 

http://btsautoparts.com/products/sw-5229-motorcraft-back-up-switch-new

 

http://shop.advanceautoparts.com/p/carquest-by-bwd-back-up-light-switch-s26077/18971428-P?searchTerm=back+up+lamp+switch#

 

Below is a link to a picture of the backup lamp switch in our car.  The harness visible above was pulled out of the switch.   From a variety of sources, including the Ford manual, we were expecting a two-wire switch, whereas the harness has a five-position connector, which seems very odd.  Only four of the wires goes into the switch, and it’s possible two of those are ghosts (if there are only two pins on the switch itself, like there are on the ’98-99 switch).

 

 

Thanks again.

Edited by Ferret II

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.