T025, T027 Traction Control Dissabled

T025 LF Wheel Speed Sensor Fault
T027 LF Wheel Speed Sensor Continuity Fault

Does this mean I need a new wheel bearing?

No. The codes strictly refer to an electronic problem related to the sensor or its wiring.

Wheel bearing faults are usually accompanied by unusual rumbling noises and would not be detected by the electronic diagnostic equipment.

But isn't the sensor integral to the bearing/hub assembly? Or is there a speed sensor in the hub that can be replaced. My Haynes manual says it can't be repaired/rebuilt, for what that's worth. I inspected the wiring and connectors in the wheel well and I didn't see anything unusual.

I forgot to mention:

This problem started last time I had an emissions test. The technician had a difficult time turning the traction control off so he could run the dyno. I've tried turning it back on with the button in the glove box but no luck. Is there some trick to it?

I also forgot to tighten the lug nuts down after a break change (I know, I know... stupid. I blame my kids for distracting me.) and broke and replaced a lug nut stud.

The sensor is fixed and is separate from the hub. It reads the rotational speed of magnetic triggers embedded (I think) in the hub. It's unlikely that ALL the triggers have fallen off the hub, but you can check this by comparing your bad hub to the 'good' hub on the other side of the car. Do they look the same?

Also, the 'continuity' problem describes a wiring or electrical defect. Likely the ECM is reading an open circuit for this sensor. It's possible if the sensor got hit hard when you did the brakes or left the wheel loose, it might have become damaged.

Finally, when you use the glove box button to turn off the traction control, the transmission will also eliminate first gear. This means that it will accelerate away from a stop in second gear. Your revs would be low and the acceleration would feel sluggish.

If you accelerate from a stop in first gear, then chances are the button and ECM are working properly.

The sensor is fixed and is separate from the hub. It reads the rotational speed of magnetic triggers embedded (I think) in the hub. It's unlikely that ALL the triggers have fallen off the hub, but you can check this by comparing your bad hub to the 'good' hub on the other side of the car. Do they look the same?

I didn't take the hubs of when I checked. So I guess the sensor is behind the hub?

HOLY COW, that sensor is $54! (cheaper than a hub!)

Also, the 'continuity' problem describes a wiring or electrical defect. Likely the ECM is reading an open circuit for this sensor. It's possible if the sensor got hit hard when you did the brakes or left the wheel loose, it might have become damaged.

I'll put the multimeter on it and test for continuity.

Finally, when you use the glove box button to turn off the traction control, the transmission will also eliminate first gear. This means that it will accelerate away from a stop in second gear. Your revs would be low and the acceleration would feel sluggish.

If you accelerate from a stop in first gear, then chances are the button and ECM are working properly.

It blows most cars away from a stop, so that's not it.

Thanks for all your help!

I had the time to work on it but could only find the hub/bearing assembley locally, nobody had the sensor alone. I kind of wanted to replace it anyway...

So I replaced the hub and tested for continuity. I disconnected the connector inside the engine compartment and at the hup. I jumpered the connector at the hub and tested from the one in the engine compartment. It was continuous from there to the hub and towards cpu.

I've reset the codes a few time but T027 "LF WSS circuit continuity fault" still comes up CURRENT.

What do I do now? I guess I need to test the sensor in the hub...

The ABS fuse is good...

I would suggest getting a factory manual or a subscription to Alldata.com , they have a step by step trouble tree for the codes that will eliminate guess work.

Break symptoms: Randomly, the breaks will pulsate and fail.

Could this be from unevenly worn rotors?

Fail means what?

I'm not sure fail is the right word. They seem to pulsate on and off very quickly, several times a second. It doesn't happen a lot, maybe one percent of the time I break. I'm not sure if they actually work when I do that because my reflex is to immediately release and reapply them, at which time they work normally.

Something else I noticed: The ABS light goes off every time I turn the engine off and doesn't come back on until I break several times, even if the pulsating I described above does not happen. Sometimes it will come on a few seconds after I start other times it can take miles.

This morning, my ABS light and traction control dissabled warning came on while accelerating. WTF?

I stopped for gas and took off again (no lights or warning) and came to a red light. After nearly completely stopping, the breaks failed. The pedal went to the floor and the pulsating started.

I've also noted that when the warning lights are on and breaks are engaged, the whole car will wobble, almost like having a warped rotor (which I have changed recently) except it is not side to side but a change in speed. It doesn't do this when the ABS light is not on.

I'm begining to suspect maybe there is a leak in the hydrolics but I have yet to see an indication of one.

I'm totally lost and confused.

This type of problem requires scanning with an abs function scanner to watch sensor and control activity, this is not a dyer type project as a rule.

This type of problem requires scanning with an abs function scanner to watch sensor and control activity, this is not a dyer type project as a rule.

Cars are evil, I swear they hate me. It doesn't matter how much money I spend trying to maintain them, they are never good to me.

Maybe I can get my wife to help me smash it into my Ford Windstar.

:crying:

Could it be that my Break Master Cylinder is starting to go bad? Maybe the wheel isn't slowing down like it should when the breaks are applied and the LF is just the first sensor in the loop?

I've never had a master cylinder go bad, so I don't know what it's like, but I described it to a friend and that was what he said it sounded like.

You do not have m/c symptoms, see my last post.

OK, here's where it gets really weird...

I recently topped of the fluid, didn't require much but noticed it had gone down a little again.

I decided to check for fluid leaks so I doused the combination valve and lines connected to it with engine degreaser and waited about 20 minutes and hosed it off very thoroughly. I closed the hood and let it dry over night.

I made my 55 mile commute to work this morning, usually the ABS light and TC Dissabled warning come on before I can get to the highway, this morning I had no warning lights on and no break failure.

So I guess it was dirty!

I haven't looked for leaks or checked the codes yet, I'll report back in a little while.

I haven't checked

T027 is now "HISTORY".

No sign of leaks.

It's a miracle! ;)

The lights came back on after a couple of days. :(

I I'm begining to see a little build up of fluid on the pump for the break pressure regulator, it was filthy before I cleanded it few days ago. Also, a couple of the break line connectors on it don't look as tight as the others. I'm going to clean the BPR ground strap connection and tighten up those two break lines and see if that helps.