Manager Forum

I have a 2001 Highlander in my shop with AWD, VSC, Skid Control.

There is no codes present but the ABS activates at random speeds on dry surface and when it does it actually inhibits your ability to steer. I ran a diagnostic test on the DLC3 and found 10.8v across TS and CG (ok) so next I checked the ABS MIL by basically jumping it. This should make the ABS light blink but it did not. As far as I can tell this means the ECU Module may be no good but I am concerned that it could be a tone ring or bad sensor. With the price ($1400) of a new ECU I just want to see if anyone has any ideas before I spend this customers money and then it is something else.

Any input would be great!

I would monitor wheel speed while the symptom occurs. That'll narrow it down to the wheel affected. The scope the signal to see what is happening. You should be able to determine a couse of action at that point.

Also, I've had a few of these where the tone ring actually broke and was spinning on the axle shaft (lexus iteration). You can't see the ring in the rear because it's captured in the knuckle. The ones I had where intermittent failures too.

One other thing....check the steering angle sensor data. Some sensors will fail and send a glitch that'll activate the ABS. Watch that data too.

Look for a cracked or moved exciter ring. I've seen this a lot and it creates the exact problem and won't trip codes.

I had one that we traced back to a loose ground on the right rear tailight that was not fixed right in an accident.

were brakes recently done on this vehicle? or bearings? The cord to the sensor could have been stretched, or when it was pluged in the terminal could have moved causing it to break contact going over bumps or from wind.

This is an old post that recently got dug up. I hope this thing has been fixed. If it has, can the OP update us please?