2000 town car ABS and check trac

[bluesboyst]

My 2000 town car ABS light and Check Trac lights come on after I drive down the street. It will stay on until I shut the car off then reset. If I just start the car and idle it will not come on.... Any ideas about this?

[Blue)(Fusion]

The ABS and Traction Control systems are disabling themselves. They do a self-test the first few feet you drive and if the ABS computer finds the sensor input data to be wrong it does this as a safety measure.

To find out what is wrong you need to read the stored code from the ABS computer. A normal scan tool available at your local auto parts store is likely NOT ABLE to check for these Ford-specific codes. The stored code will tell you why specifically the ABS system disabled itself. It is likely bad data from the wheel speed sensors due to dirty excitor rings or wheel speed sensors. I have a failed sensor on my car from last winter and have yet to replace it. Just use caution in the mean time as ABS and Traction Control will not activate.

[olopezm]

The system is designed so it performs two different tests: one at the moment you start the engine, if everything is OK the light will stay Off, otherwise it will light up (this first test is mainly to make sure the abs module is OK); the second test is performed when the vehicle reaches 13+ MPH, if any problem is found the ABS light will light up (this one is to make sure the wheel speed sensors are OK).

So... one of your wheel sensors might be bad OR MORE LIKELY the connector of one or more sensors is dirty. Give a good clean to with electric contact cleaner and put some silicon grease around the seal to prevent water from entering to the 25 pin connector of the ABS module at the driver's side in the engine compartment near the radiator.

Measure resistance with a digital multimeter between the pins of each sensor, the value should be between 800 and 1400 ohms, any value outside these means a bad sensor.

RR SENS.- 1 & 17

LR SENS.- 2 & 10

RF SENS.- 3 & 18

LF SENS.- 4 & 11

Also check continuity to ground for each sensor, if any continuity is found replace the sensor:

RR SENS.- 17 & 8

LR SENS.- 10 & 8

RF SENS.- 3 & 8

LF SENS.- 4 & 8

PIN 8 IS GROUND

As a side note, I had the same symptom in my Pontiac and the problem was a bad wheel hub bearing, I'M NOT SURE if this could apply to the Town Car... Do you have any play in any of the wheels or have noticed any humming sound or low pitched noise while driving the car?

Best regards,

Oscar.

[bluesboyst]

Thanks for all the info... I thought it may be the ABS module but now it seems to be a sensor, since the lights come on only after I start going... All the hub bearings are fine...I already replace my right one a few years ago....left one is fine...

When you say check continuity. what is that?


Thanks,

Steve

[olopezm]

Hi Steve,

the continuity test is an option in digital multimeters, it can be also known as the "beeping" function. Actually is the same thing as measuring resistance between two points, if the value is 0 or the closest possible to 0 then the multimeter will beep.

So... you can either use the continuity function or just measure resistance between each pin and ground (PIN 8) and the value should be the closest to 0 as possible.

Best regards,

Oscar.

[algermilitia]

I know this topic is old, but I'm now having the same problem now.

What happens is that the trac system starts operating randomly. usually the Trac and ABS then disable themselves. However, from time to time, the trac active light will still come on and you can feel the car pull down. My speedo is also prone to bouncing around as if the speed sensor is dying. When the speedo is acting up, the cruise control keeps trying to compensate by accelerating and decelerating.

Anyway, we can kill the trac system by pushing the trac off switch in the glove box. But, the ABS systems and trac control system will still pop up on the dash and stay on until the car is shut off.

We've taken it to a shop and the code indicates a bad wheel sensor on the left side. So, we had the sensor replaced. The problem still existed saying it was the left rear sensor. So, the shop switch the left and right rear sensors and it still threw a code for left rear sensor. The shop then said they would trace the wires, and they all ohmed out and no chafing was found. The shop then said that according to the repair books the module should be replaced. So, for over $1000 we had the module replaced with a certified used one. We are still getting the same code. We just put new tires on the car and had the tone ring looked at. It appeared clean and no cracks. So, now we're at a loss. The shop is at a loss. And $2000+ later, we still don't have a very reliable or safe car.

Does anyone have any other info to offer on this problem?