ABS Light On with codes C0210 & C0215- Resolved!

Hi, first I started to notice when at a light or four way stop behind other vehicles or driving the truck into the garage and move forward via only the brake pedal at very low speed between 1-5mph the rear brakes would at times act as if locking up. It does not always behave like this. Braking at high speed or any other speed feels and behaves totally normal. There's no vibrations or shaking of the steering wheel while braking. At this time there was no CEL or ABS or VSC other than the SRS airbag light (issue identified in another thread). Initially purchased a scanner to identify the SRS airbag light code(s) and noticed there was two additional codes pertaining to the ABS/VSC/TRAC system. The codes were C0210 and C0215.

Apparently these codes are for the rear wheel speed sensors. Truck doesn't even have 100k original miles and find this issue interesting to say the least. Took a peak underneath visually inspect the connectors and harness wiring but it all looks fine. The connector where both rss merge looked good with no signs of corrosion or anything but still sprayed it with CRC QD Electronic Cleaner spray. Truck has zero rust. I followed the wires underneath up to where they enter the front driver side floor and did not physically notice any tears or anything abnormal. Not sure if I should pull the driver seat and check the wires there since that's where they enter to inspect?

Anyway, I carefully and patiently wiggled both rss to check the rubber o-rings and they looked totally fine. O-rings had no visible signs of wear, tears, deformity, cracks, pin holes etc. The sensor itself was every so slightly dirty but no physical abnormal signs. I cleaned them with CRC QD Electronic Cleaner spray. The surfaced where the sensor sits on looked fine. The ring inside looked quite clean but used some Q-tips and wiped all the grooves/slits anyway. I inserted them back and tightened them snug but IIRC the bolt that holds the sensor has a high torque value for such a small bolt.

Truck jacked up on stands and spinning tires yields no grinding/grueling sound which might indicate a bad bearing. I did attempt to clean the magnetic ring on the bearing with Q-tips but really couldn't. I pulled the rear drums to check for bearing play by spinning the hub forward and backward but it seem to have the "normal" amount of play before engaging??? I couldn't see any movement inside while trying to move the hub up and down. I'll see if I can post a clip of what I recorded. I found a dealership receipt indicating that both rear wheel bearings were changed at 75k miles.

Drums and brake shoes looked good on wear except one drum had a visible crack inside and not sure that would trigger a rear speed sensor code. Wheel cylinders looked good. No oil leak around the seal. On another note, I'll be replacing both drums with the updated ones.

I connect everything back, turn the truck on, and now ABS light is on. I go for a drive and it feels fine. I scan for codes again and pull the exact same codes.

What is the proper way to test the sensors with a meter and values should I look for? Should I look at anything else or test anything else?

ABS/VSC/TRAC: C0210 (RH)- Current and CO215 (LH)- Current

 

This is how the sensors looked when I removed them. It looked like they were smeared with oil?

 

How are the rear wheel bearings? (Lift the truck and push/pull on the top/bottom of the wheel). I’d replace the diff breather to start. There shouldn’t be oil on the sensor.

 

Diff breather was a little dirty. I can order a new one and replace it.

The rear bearings were replaced at 75k miles and now almost at 92k miles. I'll see if I can post a video clip of the bearings.

 

https://www.youtube.com/watch?v=yr5uu8Km4W8

 

https://www.youtube.com/watch?v=7s0zVhlTS94

 

If there’s gear oil on the sensor, oil is getting past the seal. It’s been a while since I replaced my bearings, but I remember replacing multiple seals. There is a spacer that rides on the seal. If the speed sensor gear wasn't pressed on correctly, the spacer would be off the seal a bit and let oil by. It might explain your wonky rear brakes as well if oil got on the shoes. You want your wheels on when checking the wheel bearings for play (gives a little more leverage and you can really see if things are wiggling). Did you notice any odd noises like a: womp womp coming from the rear? It would increase with speed.

 

No gear oil or signs of wetness on the brake shoes or inside the drum. I can jack up the rear again tomorrow with the tires on and use a long pry bar to see if I notice any movement. I can also do my best wrestling it around and see if I feel anything. No odd noises coming from the back or at all that I recall. I know the tip of the sensors were smeared with oil but the ring inside was bone dry so that's interesting.

Would that amount of oil ruin the sensors?

*Only vibration that comes on starts at 30 mph and I can feel it coming from the front end. I have new steering rack/front sway bar bushings ready to install.

 

hmm, I would clean those sensors and clear the codes, see if it comes back. No need for a pry bar, pressing and pulling on the top and bottom of the tire should tell you if you have movement. That is low mileage for bearing replacement though. My experience is limited since I don't have ABS on mine but I do remember the ring position is important for the spacer/seal alignment.

 

Agreed, on the bearing mileage. I'll see if I can clear the codes tomorrow as well as test the bearings. Since I cleaned both sensors I can pull them out again to check for oil in a few days time and of course going to replace the diff vent. I'm ok with replacing the wheel bearings myself but it would be annoying to find the dealership didn't do the job correctly at 75k miles.

Any idea on how to test the sensor itself?

 

Unsure about testing the sensors. It would be odd for both to die together. Is there an abs fuse specific to the rear?

 

Yeah, exactly my thoughts on both sensors going out at the same time.

Not sure about an ABS fuse. I'll have to take a peak under the hood tomorrow and or do more research.

 

I came across this thread mentioning slow speed ABS activation after doing front end work. He attributed the slow speed ABS activation to the sensor o-ring being too stretched out not allowing the sensor to fully seat in place, sensor alignment, and performing a zero point calibration for the speed sensors. Based on the o-rings images he posted I can say that the rear speed sensor o-rings look to be about the same size as his "stretched out" o-ring. Also, I'm wondering if the ABS light came on for me because I was not able to full insert the sensor getting it to sit perfectly flush on the surface because the o-ring is still ever so slightly visible. Before I pulled the sensors I did not have the ABS light only the slow speed ABS activation and the sensors were fully seated with no o-ring showing at the surface of the base. I'm gonna carefully wiggle the sensors to get them to sit perfectly flush and see if the ABS light turns off. If it does then perform a zero point calibration.

https://www.tundras.com/threads/slow-speed-abs-activation-fixed.131442/

 

Sounds like a plan. I'd keep an eye on that oil getting in there. If that's the case you will eventually have to do the bearings.

 

The rear wheel bearings felt solid. Placed truck on jack stands with tires on, I grabbed the tires at 12 & 6 o'clock and 9 & 3 o'clock, and no movement of any kind was appreciated. Also, put a long pry bar under the tire running with the tread and across the tread with zero movement noted while looking at the tire and behind the drum backing plate. No wetness behind the backing plate around the 4 bolts either. Everything was dry. I'm gonna call the rear bearings good.

I pulled both rear speed sensors back out and they were both dry. Taking another look inside and everything appeared dry as well. I took a wire brush and went to town brushing the surface clean where it rests and also inside where the rubber o-ring is nestled. I carefully wiggled it back and forth until the sensor sat all the way down inside and the rubber o-ring was no longer visible. The bolt was just snugged down. I turned the truck on and the ABS light was still on so I went for a drive. Backing out of the garage and braking multiple times felt good and driving at various higher speeds also felt good. I kept driving at or above 30mph for a short bit until I headed back home. When I got to the last stop sign before arriving home I heard a noise (perhaps the ABS module/pump?*) like something activated or perhaps reset. I'm not sure what it was but the ABS light turned off. I pulled into my driveway and drive back and forth only with the brake pedal and it feels super smooth now. I turned the truck off and on a few times to see if the ABS light would come back on but it never did and would always turn off instantly as it should. Ok, awesome. I go get my scanner and auto scan which pulled the same codes but I erase/reset the codes and re-scan. Now it says, "ABS/VSC/TRAC: pass no fault". Heck yeah I'm gonna call it good. I went for another drive and all is good.

I never performed a zero point calibration but while driving I was traveling at a minimum of 30mph. Had the above not done anything for me then a zero point calibration was next.

For good measure I will still be replacing the rear diff breather.

*Theory on slow speed (1-5mph) ABS activation*
I think that in my case the sensor being smeared with gear oil and perhaps the rear wheel speed sensors having the slightest dirt/dust/grime etc built up on the surface is enough to throw the sensor signal off. Driving at such slow speeds with a dirty sensor likely has a bit of a tough time picking up the signal from the ring inside because there's minimal rotation vs traveling at a higher speed. I'd say that even though the surface doesn't look like it's dirty enough to you to cause a miscommunication still brush it clean. IDK, just my thoughts.

Should anything change I'll be sure to report back.

"ABS/VSC/TRAC: pass no fault"- Resolved, codes C0210 and C0215.

 

Quick update, have been driving around with no ABS light and braking feels good. However, I've heard the same "noise" clearly coming from the front which is perhaps the ABS module/pump or something else "activate/deactivate or turn on/off" when coming to a stop. The noise is similar to a humming sound. This has only occurred when coming to a stop a couple of times and braking feels fine during this noise. No dash lights or anything else indicating that something is wrong during these "noise" episodes. This is something new because I've never heard such noise before. I'm not sure if this is normal function or perhaps a different issue is brewing?

 

I found a thread with a video that makes the exact noise I'm talking about. Lol like it almost sounds like a cow.

https://www.reddit.com/r/tundra/comments/10oonbt/05_tundra_this_buzzing_noise_when_i_press_the/

 

It's been a minute since I updated this. Anyway, I reached out to the person over on that reddit post and replied back saying that the issue was the wheel speed sensors.

After a bit, I finally got around to taking the truck to the stealership for diagnosing with the Toyota tech-stream software to monitor all of the speed sensors. They told me that they were able to reproduce the sound/noise I described up above (identical to that reddit post) and during that episode the rear passenger wheel speed sensor signal falls flat temporarily. They also stated that it was more frequently acting up when turning right. On another note, the stealership told me that they have put a cap on age of vehicles that they work on or diagnose. I guess having master mechanics doesn't mean sh*t anymore so why have them. They had to get approval to diagnose the truck lol.

Anyway, I've ordered a new Toyota rear passenger wheel speed sensor w/out vsc trac (#89545-35020) from Japan and should arrive tomorrow. Ordered through Amayama and the total was $206.64 shipped and final.

Lol interestingly enough it hasn't made that hiccup since it left the stealership but it's still getting changed out.

 

The stealership in my town won’t work on any FGT claiming too many plastic parts too brittle and risk breaking electrical connectors.

 

Solved. Update, the ABS noise and brake sputter issue has not returned since installing the new sensor.

I also took the time to properly adjust the rear drum brakes per the FSM instructions floating around on one of the threads here on this forum. Adjusted as follows; disconnected both emergency cables from the parking bell crank levers, adjusted the star adjuster to where there is little friction between the brake shoes and drum, from behind I pulled on the parking bell crank lever until there was no slop at the small cable that sits between both brake shoes inside, adjust the bolt at the parking bell crank lever so that it has about .5mm of play before touching the backing plate, reconnect the parking brake cable ends to the parking bell crank levers, adjusted the parking brake cable length underneath the cab on the drivers side until it was taught between both rear drums, and lastly pressed on the parking brake pedal a few times so that it finished adjusting/calibrating. I did not have to adjust the brake pedal. The braking now is amazing. Also, an odd vibration that was taking place between 30-40 mph has gone away and the whole time I was thinking it was perhaps the steering rack bushings which I also bought but never installed.

Anyway, truck is fantastic. I will update should anything change or something new arise. I appreciate all the help on this forum.

 

One thing I recently did was replace the soft lines, 1 in the rear and 2 in the front. It’s made a difference in brake response. Mine were original, dated 1999. I used factory lines, but there are aftermarket ones as well.