Grease on rear ABS/wheel speed sensors.

Update for anyone who is interested:
I mentioned about grease on the rear ABS sensors and the codes listed below. It turned out to be both axle seals were blown out. Oil from the diff was travelling into the area where the ABS sensor reads the tone ring speed. Anyways, the sensors should be free of oil and grease. If you have either on your ABS sensors you should check your axle shaft seals or hub assembly. Thanks.

Hello All,
This is my first post. I've had my Tacoma for about a year now, I use this forum quite often to research info on my truck. I have a 2010 DCSB, six speed.
I've been dealing with some wheel speed sensor issues lately. I have the following codes:

C0215-left rear wheel speed sensor signal malfunction
C1239-foreign object attached on tip of left rear wheel speed sensor

The parking brake, traction control and ABS lights are on all the time. I removed both the rear driver and passenger speed sensors. Both have a milky white grease covering the sensor. Is this normal or does it indicate a bad seal (either bearing or axle)? I cleaned both sensors and re-installed, the codes/lights did not clear.

Before I go ahead and purchase a new speed sensor I want to know if I have an underlying problem with the grease on the sensors. I jacked up the truck and spun the rear driver side wheel, the bearing seemed fine. I've read on this forum that the grease is normal, while other have said its not normal. Any advice would be appreciated. Thanks.

 

crickets...

 

@markus30 may be of some help. He's a pretty smart dude

 

The axle seals protect the ABS tone ring on the bearing, if the seals fail the sensor and tone ring will become contaminated.

Is there oil inside the drum? Inside the rim?

The sensor may not be the issue, but the pick up ring on the bearing instead.

 

thanks for the reply. there is no oil inside the rim. i didn't look inside the drum. i find it strange that the grease is on both driver and passenger rear sensors. is that a coincidence or have both wheel bearings failed?

i've read some posts stating that grease is normal and other posts say it isn't normal. any clarification on this would be appreciated.

 

update on first post...

 

Id like to know as well, same issue except no oil, just thick nasty grease was on both sensors. Mines only throwing abs light though, and the rear locker wont engage, just flashes light and think it has something to do with the abs sensors. Ive tested the locker motor and sensor/ switch and both are fine so something in the system isnt happy. Mine is only throwing codes 33,34. Which is rear right and left sensor not communicating…. Both sensors ohmed out fine, cant see any more grease inside but codes wont go away after cleaning..

 

you'll need to reset the system as the codes for ABS are latching.

 

Actually the codes for the abs are not latching.. turned out the wiring that comes from the harness under the drivers seat (b07?) then goes right by the charcoal fart box, apparently i was missing both bolts that hold the bed on to that drivers side and must have hit a bump and bounced the bed up enough to come back down and cut every damn wire from the fuel tank back. The previous owners ran 4 wires for brake lights n stuff but found the problem. Was getting codes 33&34 no comm with rl and rr spd sensors. When i rewired them and hit the key the abs light went off n stayed off. And my rear locker works.. check engine light went off too.. just got done changing on the fuel filter (didnt depressurize anything and just spit up a small bit.. on my face..). But did timing belt, water pump, crank n cam seals, new belts, transmission filter , valve cover gaskets, air filter, new dash lights, tightened all suspension and added bolts that fell out.. new tie rods, greased driveshaft, changed the diff fluid. Oil change. And changed out the factory radio for a dvd player with reverse cam and rock well cams.. about to sell the thing.. 187000, 2wd, 6”rc lift, no rust, bed cover, 4dr, silver w/ cloth seats, everything works now.. got a hitch, bushwa kers,, window visors, tinted, power windows n locks, rs3200 security system.. clear coat gone on hood and roof. Only rust is surface on drivers bed rail.. still has the bed liner.. 33-10.5 bfg mud tires. Full size spare. Step rails, bull bar to the frame, uhaul 10k drop hitch. Led headlights. 15k$…. 2 owners, clean title, all service records.. 2 yr old battery. Sliding rear glass

 

What ohms do you want to see on a speed sensor? I need to check ohms on mine

 

You can't just test with an ohmmeter. You need to use an O-Scope or an intelligent tester connected to the DTC Port. If you have grease or oil coating the sensor you need new axle seals etc, if you see metal shavings you have a damaged wheel bearing.




How to test:

 

I have all of the above mentioned. That’s what I figured it was. I replaced the sensor and it still didn’t work. Thank you for that information.

 

Appreciate the update.

 

Well it ended up being a bad rear passenger wheel bearing. Kind of surprising for a truck for a 5 year old truck with 140k miles on it and mostly street driving

 

Yeah this happened with my 07 prerunner. Bearing seal failed and grease got out. No codes on my end but it was making my ABS system go off at the worst of times so had to not drive it until the bearings got fixed. When you go get it swapped make sure to use OEM bearings or reputable aftermarket brand.

 

Several months ago I replaced a bad sensor on my 2008 taco. The rust on the bolt made it impossible to unthread, I air chiseled it off and of course chiseled the sensor in half. I could not pull the remaining part out and I took a very small screwdriver and broke it apart and pulled the pieces out with forceps and compressed air. Put a new sensor in and ABS went off almost immediately. Genius repair right? Wrong. I was crawling underneath the truck today and noticed some leaking around the sensor. Took it all apart ( I forgot I had to tap and add a screw to hold sensor in) the sensor was covered in differential fluid. Put it all back together and there is no leak and ABS is light is still off. Thanks to this forum for showing me the error of my ways and will take it to the shop for seal replacement. I’m wondering if I damaged the seal removing the old sensor. I was pretty delicate with it but who knows….