ABS Codes After Wheel Bearing Replacement

[Devbot]

Hi all. Just replaced my wheel bearings the other day and immediately upon my first drive I lost ABS - perfect timing too with temperatures dropping fast. I did the paperclip trick to jump the diagnostic ports to get the codes, and this is what I got so far and what I believe the codes mean based off some digging:

Code 31 (LF speed sensor fault)
Code 32 (RF speed sensor fault)
Code 34 (RR speed sensor fault)
Code 41 (Low batt voltage to circuit)
Code 49 (stop light switch ciruit open)
Code 51 (Pump motor locked/circuit open)

I'm very hesitant to believe all these things just happened to go bad all at once, and am leaning towards a single common denominator causing me trouble. Does anyone have an idea where I even start chasing an ABS gremlin? Across all the ABS threads over the various forums very few (if any) of them have any sort of resolution to their problems, with most people saying "check it with a multimeter or something, idk" which isn't very reassuring. So far I've tried cleaning all the electrical contacts I could, cleaned up the ABS pump ground, and pressing the pedal 8 times in 3 seconds to reset the pump (read this on some Toyota forum as a fix, not sure if it's legit)
I do have two spare speed sensors in my garage too - but it doesn't seem likely that all but one just suddenly died, including one that I haven't touched in over a year... Seeing as there's so many codes and they can be bought off ebay fairly cheap I was thinking of perhaps swapping the ABS ECU to see what happens, but I'm skeptical that will do much either. Thoughts?
Everything is still behaving as it should be; car stops fine, brake lights still work, speedo works, etc. I pulled the two front sensors to see if maybe they were coated in grease or something but they were completely clean. Before my wheel bearing replacement I had absolutely no issues - only note of relevance was a week-long point maybe a year ago where the ABS light came and went on it's own. Didn't pull any codes then.
Am I correct in saying if my speedo and brake lights work despite codes telling me they shouldn't, that should indicate the pump or ECU is bad?

 

[JT1USA]

Not sure if this helps but in my understanding the ABS light comes on when one or more of the wheel speed sensors have malfunctioned, brake fluid is too low, fuse is blown or the relay is bad, or if the ABS module has developed a defect. I'd check the fuses and relays first (cheap). Then replace the speed senors with the ones you have. I doubt its low brake fluid. Check the speed sensor connections to make sure none of the wires got damaged or pulled out of the connector during disassembly. Trouble shooting is not fun.

 

[brillo_76]

I agree all those are not going bad at once. If the fuses and relays are good. I would probably swap the abs ecu. What year is your rig?

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[19963.4lsr5]

I’m pretty sure 51 is the ABS motor


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[Devbot]

I agree all those are not going bad at once. If the fuses and relays are good. I would probably swap the abs ecu. What year is your rig?

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That's what I was thinking, for the $40-50 they go for it's worth a shot
I drive a 2000 Sport

I’m pretty sure 51 is the ABS motor


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Yeah I've read for some Toyotas it's the dead ABS motor, some it's the ABS pump right next to it, others it's a faulty signal of some sort. A few days ago I came across a sheet of all the ABS codes for our vehicles but I can't find it for the damn life of me now :ranger:
Motor wouldn't be a big deal. Pump would suck a little - would probably have to get one second-hand, assuming Toyota wants an arm and a leg for a new unit
Is there a way to test the motor or relays, that you know of? Knowing these cars it's probably not as simple as just applying 12v somewhere if so...

 

[19963.4lsr5]

Did you pull the battery cable to reset all codes and see if they come back?

The fact that the light blinks codes the abs ECU isn’t dead…..


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[Devbot]

Did you pull the battery cable to reset all codes and see if they come back?

The fact that the light blinks codes the abs ECU isn’t dead…..


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Yep, had it off for over an hour. Good thinking, I didn't consider that. Maybe I will try the motor first after all

 

[RandyBobandy]

I’d be surprised if the service manual didn’t have a procedure for testing the abs pump, also kind of weird that it would fail right after a wheel bearing replacement. My guess would be something with the placement of the tone ring or something wrong with a sensor causing the issue.

Lots of vehicles you can’t just replace the motor or the pump separately they need to be replaced as a whole unit, never did one on a 4Runner though

 

[19963.4lsr5]

If you unplug the abs module and reset the codes what changes with the codes? Anything?

I remember a thread similar to this a few years ago…..


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[theriddler]

Hi all. Just replaced my wheel bearings the other day and immediately upon my first drive I lost ABS - perfect timing too with temperatures dropping fast. I did the paperclip trick to jump the diagnostic ports to get the codes, and this is what I got so far and what I believe the codes mean based off some digging:

Code 31 (LF speed sensor fault)
Code 32 (RF speed sensor fault)
Code 34 (RR speed sensor fault)
Code 41 (Low batt voltage to circuit)
Code 49 (stop light switch ciruit open)
Code 51 (Pump motor locked/circuit open)

I'm very hesitant to believe all these things just happened to go bad all at once, and am leaning towards a single common denominator causing me trouble. Does anyone have an idea where I even start chasing an ABS gremlin? Across all the ABS threads over the various forums very few (if any) of them have any sort of resolution to their problems, with most people saying "check it with a multimeter or something, idk" which isn't very reassuring. So far I've tried cleaning all the electrical contacts I could, cleaned up the ABS pump ground, and pressing the pedal 8 times in 3 seconds to reset the pump (read this on some Toyota forum as a fix, not sure if it's legit)
I do have two spare speed sensors in my garage too - but it doesn't seem likely that all but one just suddenly died, including one that I haven't touched in over a year... Seeing as there's so many codes and they can be bought off ebay fairly cheap I was thinking of perhaps swapping the ABS ECU to see what happens, but I'm skeptical that will do much either. Thoughts?
Everything is still behaving as it should be; car stops fine, brake lights still work, speedo works, etc. I pulled the two front sensors to see if maybe they were coated in grease or something but they were completely clean. Before my wheel bearing replacement I had absolutely no issues - only note of relevance was a week-long point maybe a year ago where the ABS light came and went on it's own. Didn't pull any codes then.
Am I correct in saying if my speedo and brake lights work despite codes telling me they shouldn't, that should indicate the pump or ECU is bad?

Same thing happened to me, i replaced both wheel bearings and all the seals but now i have an abs code....weird. I'm confident everything i did was to spec with Toyota parts. I'm wondering though if i didn't damage a sensor or sensor wire when removing them. Mine rig is driveable though, that's why i haven't dug into too far yet....i just have an ABS light on the dash.

It might be worth the money to take it to the dealer and see if they have any scanners or diagnostic equipment to pinpoint the problem. I'm not much on throwing new parts at something trying to fix a problem...very expensive and aftermarket parts are never as good as oem Toyota parts.

 

[Devbot]

If you unplug the abs module and reset the codes what changes with the codes? Anything?

I remember a thread similar to this a few years ago…..


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Yeah I already unplugged them a couple days ago to clean off the contacts, no difference made unfortunately

 

[sbag91]

Forgive me.

Everyone in this thread probably knows more about this than me...BUT

Did you do the rears yourself? Did you put the tone-ring back at the same length from the end of the axle? Does it matter if its located differently around the axle? I was planning on just marking it and putting it back in the same location... Most of the YT/people I've asked about this just say to cut off the race/bearing....a few even the tone ring. I can't justify buying Doorman tone rings at roughly $45 a pop off rockauto when I can save the OE ones with an $87 tool.

I've just today bought a plasma cutter to help speed up some of the process of fabricating tools for this (as well as other projects, just hoping it comes in handy). I have the 12ton HF shop press, which I read takes some modification to be able to work with one of the amazon/or OE tools for pulling the bearings/tone ring.

After just finishing up the lift today, I can say, the brake lines were defiantly more taught....but all my ABS sensor lines had PLENTY of room. I cant see how they would have been damaged from almost any situation I could throw at em'.

Anyways just trying to bounce some ideas around in the slight possibility it could help.

 

[Devbot]

Everyone in this thread probably knows more about this than me...BUT

Did you do the rears yourself? Did you put the tone-ring back at the same length from the end of the axle? Does it matter if its located differently around the axle? I was planning on just marking it and putting it back in the same location... Most of the YT/people I've asked about this just say to cut off the race/bearing....a few even the tone ring. I can't justify buying Doorman tone rings at roughly $45 a pop off rockauto when I can save the OE ones with an $87 tool.

I've just today bought a plasma cutter to help speed up some of the process of fabricating tools for this (as well as other projects, just hoping it comes in handy). I have the 12ton HF shop press, which I read takes some modification to be able to work with one of the amazon/or OE tools for pulling the bearings/tone ring.

After just finishing up the lift today, I can say, the brake lines were defiantly more taught....but all my ABS sensor lines had PLENTY of room. I cant see how they would have been damaged from almost any situation I could throw at em'.

Anyways just trying to bounce some ideas around in the slight possibility it could help.

Never touched the rear sensors. Thus the problem - rears haven't been touched in well over a year yet suddenly failed along with the fronts and half the system overall, meaning it's most likely not a speed sensor issue like the codes entail

 

[brillo_76]

I can understand abs codes for front wheels if you did a wheel bearing change. How can the rear 2 be effected? Then all the sudden right after the bearing change.

Unless , if the front goes the entire system is offline. It's just very odd indeed.

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[brillo_76]

Never touched the rear sensors. Thus the problem - rears haven't been touched in well over a year yet suddenly failed along with the fronts and half the system overall, meaning it's most likely not a speed sensor issue like the codes entail

Agreed I doubt it the speed sensors, it's probably the control unit or the abs pump itself. Being the ecu is giving you codes, it possibly function properly and its the abs motor failure? Thus why everything is coding.

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[JohnMc]

It's not clear from the first post which wheel bearings you replaced, and the more common set to replace is on the rear. But I guess you replaced the fronts?

It doesn't seem likely that all those things actually failed due to the front wheel bearings being replaced, but ECU's are certainly not always great at telling what happened. It's possible that all those codes were stored from some passing incident that set the light a year ago that you mentioned, and when one new issue popped up, reading the codes shows it along with all the old ones? As mentioned, clear all the odes, verify they're gone, and then see which ones come back.

With the front sensors removed, is the tone ring clearly visible and reasonably centered in the hole when you look?

 

[Devbot]

It's not clear from the first post which wheel bearings you replaced, and the more common set to replace is on the rear. But I guess you replaced the fronts?

It doesn't seem likely that all those things actually failed due to the front wheel bearings being replaced, but ECU's are certainly not always great at telling what happened. It's possible that all those codes were stored from some passing incident that set the light a year ago that you mentioned, and when one new issue popped up, reading the codes shows it along with all the old ones? As mentioned, clear all the odes, verify they're gone, and then see which ones come back.

With the front sensors removed, is the tone ring clearly visible and reasonably centered in the hole when you look?

Yep, ABS ring looks to be where it should be. If it wasn't I should've noticed during installation since the axle spacer wouldn't be fully seated, or at the very least have heard it moving around when I was painting them. Or at least I think I should've? I assume it would have to be off by quite a ways for a bad reading, now a handful of thousandths
I tried to reset them per the FSM by jamming the brake pedal a whole bunch but nothing happened - however after thinking about it I can't remember if I did so with the ports still jumped, so I'll give it another go later today and check it out

 

[Devbot]

So far resetting the ABS codes seemed to work, but oddly enough I had to keep the shorting bar in for it to clear? Everywhere I read said to take the bar out which worked fine for me pulling codes, but for whatever reason it wouldn't let me clear them until it was back in place. At any rate I went for a short drive and the lights stayed off, we'll see how it goes!
[MENTION=115088]theriddler[/MENTION] I would perhaps try this; jump the ports of the ABS diagnostic and hit the brakes 8+ times in 5 seconds, and maybe play around with the shorting bar if it doesn't work the first time

 

[Devbot]

Welp, codes and lights are gone but ABS is now activating randomly on completely dry pavement... :frusty:
Nearly rear ended some guy on my lunch break, shit kicked on going in a straight line at maybe 10mph for a solid second
Sounds identical to this thread so hopefully they're either not seated fully or dirty

 

[19963.4lsr5]

Welp, codes and lights are gone but ABS is now activating randomly on completely dry pavement... :frusty:
Nearly rear ended some guy on my lunch break, shit kicked on going in a straight line at maybe 10mph for a solid second
Sounds identical to this thread so hopefully they're either not seated fully or dirty

My front brake lines were cracked all to hell. I had the turning right at a slow speed and braking which would activate the ABS. Since I replaced the front brake hoses with new that issue went away.

Do you have rust chips on any of your ABS sensors? That will fake a wheel speed difference that causes the ABS to activate.


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