ABS Code 31 - OSF Hub

[Alex Knight]

Hi all,

I am getting an intermittent ABS code 31 recently. This relates to the driver's side front sensor.

Does anyone know of a way of removing the sensor from the hub in order for me to clean it up?

I've come across this video, and it seems this is a similar setup to ours, which tells me it's probably better to get a new hub and sensor? Can anyone confirm?

[Carolyn]

They rarely come out in one piece, I'm afraid.  It's worth testing the resistance by unplugging the sensor and putting a meter across the connectors in the plug.

If it's an open circuit or very high resistance it's buggered.  It's also worth checking that the reluctor ring on the hub is in one piece and not jammed up with road filth, that could certainly cause an intermittent fault.

I've changed a few and I've basically had to dig them out with a hammer and screwdriver. Then it's a must to clean out the hole it goes in before installing a new one.  They ain't cheap either!

[J88TEO]

I took the hub off and secured it on the vice. PlusGased it for 2 days and tap it out with a socket.

[Joesson]

I read somewhere, recently,  about working on the front hub/ area with an advisory about removing the ABS sensor "to prevent damage". I recalled several mentions on here that such removal was at the least difficult and would likely result in renewal.
Being aware of that likelihood I've just been very careful in that area, when I finally get around to refitting the front wishbones I will know if I've been careful enough. If not I have several screw drivers and hammers.
I like that @ Carolyn suggests a test method to determine the viability of the unit.

[Dev]

I read somewhere, recently,  about working on the front hub/ area with an advisory about removing the ABS sensor "to prevent damage". I recalled several mentions on here that such removal was at the least difficult and would likely result in renewal.
Being aware of that likelihood I've just been very careful in that area, when I finally get around to refitting the front wishbones I will know if I've been careful enough. If not I have several screw drivers and hammers.
I like that Carolyn suggests a test method to determine the viability of the unit.

 If you are just replacing the front control arm it is not so delicate to be overly cautious.
There is no worry with manipulating the hub to get it aligned as it can be a bit of a pain to line up all the bolts.
 

[Alex Knight]

Hi all,

Thanks to everyone for the replies so far.

I have metered out the speed sensor in the hub, and I am getting about 1.5Ω, which rules that out I believe.

I have metered out the wiring to the sensor (with the ignition ON), and I'm getting the following:



Reading is 1.632 Kilo Ohm - basically nothing I believe? The Workshop Manual states that "Resistance: 1 MW or higher".

I then metered out the NSF (there are no issues with this side, this was just to compare) and I'm getting the following:



15.18 Mega Ohm - this looks good to me.

Unless I am mistaken, this points to a wiring problem on the wiring to the sensor (chassis side).

I think that this would be consistent with the intermittent nature of this code - possibly a wiring rubbing somewhere causing a short?

Any pointers as to where to look next gratefully received!

[Alex Knight]

FIXED IT!

Turns out that I had a slight dodgy earth on the main harness.

There are two earths that earth on the suspension turret. One of the bolts had gone a bit rusty.

Cleaned it all up, reset the code and it didn't come back!

N.B.

I was getting a low reading from the chassis side because I had the terminals the wrong way round on the multimeter! Sorry for the confusion everyone. I re-tested and had solid readings in the whole loom and sensor all the way through, which made me start checking earths.

[Alex Knight]

Well, the plot doth thicken!

I've just been back out to the car, and the f*%king ABS light is back on!

This is absolutely baffling.

Last time I was in the garage I cycled the ignition multiple times and the ABS light went out after 3 seconds each time.

I haven't moved the car, haven't touched it AT ALL. It's just been sat there doing nothing at all.

What on earth is going on?

[Alex Knight]

Just plug the suspected dodgy sensor into the harness on the good side.

See if it gives you a fault on that side too.

I can't remove the sensors, but I will swap the harnesses over and see if the problem moves with it.

[Alex Knight]

Have you got a spare hub with a sensor in it you can try? Even a back one would do.

Or put a resistor in the place of the sensor.

Probably even a crank sensor would do too. It's similar in its winding inside.

Nope, no spare hubs or anything.

I don't understand why if I'm getting the correct resistance, it's throwing a fault.

Or why the fault could come and go without the car even moving.

[Alex Knight]

I'm starting to wonder if this intermittent issue is alternator related (even though when testing the engine was off and the car is hooked up to a battery conditioner)?

*** Edit ***

Just checked the alternator voltage with the engine running and I'm getting 14.3V, so it's not that.

[Carolyn]

Drive the car and see if it goes away?  It might just be a residual fault in the ECU.

[Alex Knight]

Drive the car and see if it goes away?  It might just be a residual fault in the ECU.

That's a good call. Will do.

[Dev]

I'm starting to wonder if this intermittent issue is alternator related (even though when testing the engine was off and the car is hooked up to a battery conditioner)?

*** Edit ***

Just checked the alternator voltage with the engine running and I'm getting 14.3V, so it's not that.

I would check to see if there is any AC voltage leakage. A lot of ABS sensor issues are related to the harness and ODB connector issues. Possible ECU. 
Cleaning the ECU contacts would be my next move.

[Alex Knight]

Update:

Light is off!

I took it for a drive and that didn't clear it. I even disconnected the battery. Nope, light still on when I reconnected it.

I then came across this video:

Fixed it!

Ignition on, fully depress the accelerator three times and the light went out immediately.
Took it for a drive. Light stayed off. ABS works just fine.

Huzzah! I'm so pleased! What a faff.

I had no idea you could do this with a Toyota.

[Dev]

That is amazing. One for the record books.

 I remember long ago someone giving me the instruction of how to program a duplicate key where there is a series of pressing the pedals in a sequence and I thought I was being trolled but it worked. 

[Alex Knight]

Anon

You b*&$ard!

ABS light is back with a vengance 

I'm getting really annoyed with this now.

I can clear the code by bridging the terminals and pumping the pedal 8 times per the manual.
It doesn't always work. Sometimes it can take 4, 5 or even 6 attempts.

Once the code is cleared, I can cycle the ignition and sometimes the light will go off and stay off for multiple cycles.
Other times, the code comes straight back. Literally nothing has changed at all. I haven't moved the car or started it.

There seems to be no rhyme, reason or pattern to it.

I'm starting to wonder if it's an issue within the ABS ECU itself, as I'm getting resistance within spec at the sensor and the wiring to the sensor.

This is SO frustrating.

[Carolyn]

Anon

You b*&$ard!

ABS light is back with a vengance 

I'm getting really annoyed with this now.

I can clear the code by bridging the terminals and pumping the pedal 8 times per the manual.
It doesn't always work. Sometimes it can take 4, 5 or even 6 attempts.

Once the code is cleared, I can cycle the ignition and sometimes the light will go off and stay off for multiple cycles.
Other times, the code comes straight back. Literally nothing has changed at all. I haven't moved the car or started it.

There seems to be no rhyme, reason or pattern to it.

I'm starting to wonder if it's an issue within the ABS ECU itself, as I'm getting resistance within spec at the sensor and the wiring to the sensor.

This is SO frustrating.

You can always get an ABS control module from J-Spec.  I bet they never get sold, so it won't cost much.

[Alex Knight]

You can always get an ABS control module from J-Spec.  I bet they never get sold, so it won't cost much.

Thanks @Carolyn, I had considered contacing @J-SPEC, but I wondered how feasable it is that the unit could be failing first.

Not many people have had this problem, it seems.

[Carolyn]

Occasionally the main ECU has been known to fail. 

The ABS module would be a first ,I think.  But ANYTHING can break!

[mr2garageswindon]

If you can access a code reader and check live data on that wheel it may well not be the sensor.
I had a hilux in few months back abs light on NSF wheel doing 120 mph!

[Alex Knight]

If you can access a code reader and check live data on that wheel it may well not be the sensor.
I had a hilux in few months back abs light on NSF wheel doing 120 mph!

Was the ABS ECU at fault on this occasion?

[paulj]

Fault finding like this can frazzle your brain, so worth keeping a note of what you have tried and what the individual answers were.

[mr2garageswindon]

Was the ABS ECU at fault on this occasion?

No It was the sensor.
I'd find a replacement hub just to plug in. Most likely the cause.

[Alex Knight]

To update this thread, I relented and booked the car into the local garage.

They had an oscilloscope on the sensor, and sometimes it was giving the correct reading, other times not at all.

It points to the sensor failing, but not completely, hence the intermittent nature.

I've ordered a new hub and sensor from TCB to fit. I'm confident that this will solve the issue.