1997 Mercury Grand Marquis - ABS question

[tken35]

Is anyone familiar with Ford TSB #985A3 (NHTSA ID #601002)?

Summary: The Anti-lock Brake System ( ABS ) may activate under false ABS conditions. *YC

When I went to change the oil at the dealership the other week, I was talking to one the Dealership Technicians and he said it is a known problem but that there is no fix. Honestly, this has been going on for years and may have even lessened (a little) after we installed all new brake lines, but it is still annoying. Any suggestions?

Thank you in advance.

[Blue)(Fusion]

It may be a bad wheel speed sensor or a dirty ABS exciter ring. This happened to me last winter. Out of nowhere my Traction Lock and ABS systems randomly failed after driving a few feet. The failure would be indicated by the ABS and TRAC CTRL lights constantly illuminated on the dash which means they were disabled because of a fault.

Sometimes it would disable and no problems except those functions actually being disabled. Other times it would not detect the fault and would pulse the ABS system when making a normal stop. This can be dangerous not only annoying.

TO disable the ABS system you can disconnect a wheel speed sensor and it will be disabled instantly at start up. This is what I do now. I disconnected the driver side wheel speed sensor in my car. The connection is located under the rear seat cushion. It is very easy to access. Takes about 2 minutes to disconnect.

[tken35]

We took out the speed sensors and cleaned them as well as inspect what I thought were the exciter rings. These are the ones pressed on the hub assembling correct?

The ABS continues to turn on intermittenly as before. Any other suggestions?

No codes are present and I don't want to replace the speed sensors without being sure that that is the problem.

Thank you in advance.

[Blue)(Fusion]

ABS codes are not readable by the run-of-the-mill code readers. I have laptop software and a OBD-II device that can read SAE and Ford-specific codes including transmission, ABS, engine, and airbags systems. You may have to find someone who has the ability to read the ABS codes and hopefully the system detected a fault atleast once and stored a code. A dealership will be able to read these codes, but usually costs around $50 just to read codes/diagnostics.

If you do not need ABS and traction control (if equipped), you can unplug one of the wheel speed sensors. Easiest ones are the rear wheel speed sensors. Lift the rear seat cushion, fold the rubber flap over and disconnect the connector on either side of the vehicle. It disables the system at start up and will be safer in the mean time until you get the problem fixed.