I've had a Rear ABS light on the dash since I bought my 90 4Runner a few months ago. Pulled code 33 (open or short circuit in speed sensor circuit). Tracked down a broken wire coming out of the abs speed sensor wire connector above the frame rail and repaired wire. I assumed this was the problem. Nope, light is still on and won't go off after procedure listed in FSM to reset and disconnecting the battery.

Checked voltage at abs speed sensor connector - getting about 2 volts...does this sound right?

Checked resistance of abs speed sensor itself and got an infinite (open) reading. It should be 580 - 700.

Removed bolt of abs speed sensor and had a heck of a time getting it out of the differential. Had to pry it off with a screw driver. When it finally did come out, the part that sticks down into the diff was much shorter than I thought it would be. Essentially it was only a 1/4 - 1/2 round extension that was magnetized in the center. Feeling into the hole in the diff that it came out of, I feel a solid piece of something - the hole does not go into the diff cavity.

I suspect the abs speed sensor broke off inside the diff, hence the short piece attached to the top of the sensor and the blocked hole in the diff. Can anyone confirm what the sensor looks like (pic?) or tell me if from this description it sounds like a piece is stuck in the hole?

Thanks.

 

i dont have a pic of a good one, but if you had a pic of yours i could tell you if it is broke. and try to get one of the hole.

 

bump - it is raining out, so I can't get a pic. anyone else have thoughts on this?

 

 

Dude, it broke off. It rears the teeth on the ring gear. The trick to clearing the code is tricky. Open a short connector, cycle key on, tap brake light on 8 times before chime goes away.

 

Thank you VERY much for the pic! It is now clear the sensor is broken off in the diff hole. Bummer.

I tried clearing the code per the FSM...disconnect service connect, jump ports, hit brake 8 times within 3 seconds with ignition on. Still wouldn't clear the light - I'm guessing because the sensor is broken.

Now the fun part - do I try to drill out the sensor stub that is snapped off in the diff and risk dropping a piece into the differential. Maybe I'll just call it done and go without ABS.

Will post in Wanted Section - but if someone has a used abs speed sensor (even if it doesn't work), I'm interested.

 

If you want the abs light to go off on the dash, and you don't care about having the abs functioning in the rear, just solder a resistor across the two wires that went to the speed sensor that broke off in your differential and the dash light will go off permanently. I did this to my 92 yota. be sure the resistor you buy to do this with is between the 580 and 700 ohm range. Once you solder the resistor to the two wires, just tape it up to the axle and your problem is over with the abs dash light.