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Discussion Starter #1 (Edited)
Service Stabilitrak and Service Brake Assist error messages.
DTC C1226 and C0040, indicating RF wheel sensor problem.

Idiot me, tired from working 12 hour shifts, took it to the dealer and paid $150 diagnostic fee to find out what I could have gotten from Autozone for free.

Dealer claims they removed the RF wheel and inspected everything for damage and found nothing, so they quoted me $500 to replace it. Hmmm that's funny because I have aftermarket lug nuts and the key was still under everything in my center console. And then when I removed the wheel myself I instantly noticed that the bolt holding the WSS cable was halfway out. So either they took off the bolt and didn't put it back on all the way, or it was loose the whole time.
I put it back in all the way, cleared the codes, and they instantly came back. So sadly it wasn't that easy of a fix.

My next plan is to switch the left and right side cables and see if the codes change to the left side(once I get the OBDII tool I ordered)

But also I was thinking maybe it was loose and brake dust or something got inside the hole, could this mess it up? Should I just spray it out with compressed air?

I also saw some videos on youtube about testing the sensor with a multimeter so I will try that next.

Any other free/cheap ideas to test before I look into replacing the hub? (still a lot cheaper than $500 so I don't know wtf they're talking about)
 

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Service Stabilitrak and Service Brake Assist error messages.
DTC C1226 and C0040, indicating RF wheel sensor problem.

Idiot me, tired from working 12 hour shifts, took it to the dealer and paid $150 diagnostic fee to find out what I could have gotten from Autozone for free.

Dealer claims they removed the RF wheel and inspected everything for damage and found nothing, so they quoted me $500 to replace it. Hmmm that's funny because I have aftermarket lug nuts and the key was still under everything in my center console. And then when I removed the wheel myself I instantly noticed that the bolt holding the WSS cable was halfway out. So either they took off the bolt and didn't put it back on all the way, or it was loose the whole time.
I put it back in all the way, cleared the codes, and they instantly came back. So sadly it wasn't that easy of a fix.

My next plan is to switch the left and right side cables and see if the codes change to the left side(once I get the OBDII tool I ordered)

But also I was thinking maybe it was loose and brake dust or something got inside the hole, could this mess it up? Should I just spray it out with compressed air?

I also saw some videos on youtube about testing the sensor with a multimeter so I will try that next.

Any other free/cheap ideas to test before I look into replacing the hub? (still a lot cheaper than $500 so I don't know wtf they're talking about)
Rock auto has one for less than $50 . $500 is a pretty good profit for less than an hour's work.
 

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I’ve had good luck bringing them back to life on BMWs just by removing them and cleaning the crud out of the hole in the hub. You’ll also want to rotate the hub so that you clean any crud out between the “humps” that I assume trigger a pulse in the sensor.

Get some spray contact cleaner and clean the contacts in the sensor connector also.
 

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I've had wheel speed sensors go bad on a VW Corrado, and the symptom was the resistance was high - essentially an open. Since these are basically coils of wire around a core, the resistance is typically pretty low.

It's easy to disconnect the connectors from the side with error, and the opposite side without an error, and compare the readings. If the good one is sane ( say under a few kOhms) and the error side is very high or open, the sensor could well have failed.

Back when ABS was new-ish ( like the time frame of my Corrado, mid nineties), this was the most typical failure mode. I'd hope things are better now, but maybe not.


-Lumos
2014 gen 1
 

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Discussion Starter #5 (Edited)
That's what I'm hoping for, easy cheap fix.

Can anyone show me exactly where they plug in at? (the abs module I'm assuming) I don't feel like taking the inner fender lining to follow the wire yet without having the obd tool to diagnose more
 

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Woah, hold on. Some tone rings are just a magnetic rubber band inside the hub bearing. I wouldn't be spraying or blowing anything in a hole just yet or you're going to need a wheel bearing on top of that. Let me look it up.
 

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Okay, it's a dry senor, but it has a magnetic tone ring on the back of the bearing. It's the black part on the back that looks like a seal. It is super fragile and easily screwed up.

download (1).jpg


You have a 50/50 chance it's the sensor. I'd go ahead and swap sensors from side to side being as they are the same. If that wheel keeps throwing a fault you'll need a bearing.

Oh, and many of us technicians have the "keys" to aftermarket lug nuts so we don't need to rummage for yours. Nothing worse than having to dig through someone else's crap. It's generally true wheel locks we don't have the keys to.
 

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Discussion Starter #8
Oh, and many of us technicians have the "keys" to aftermarket lug nuts so we don't need to rummage for yours. Nothing worse than having to dig through someone else's crap. It's generally true wheel locks we don't have the keys to.
Yeah I thought of that possibility, that's why I didn't go demand my money back. But still, either they lied or they didn't put it back together, so I don't trust them to touch my car ever again.
In your experience which do you think is more likely? Just curious...

Thanks for the info on the sensor, I will try cleaning it out only as a last resort before replacing the hub.

OBD reader should be here tonight.
 

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Yeah I thought of that possibility, that's why I didn't go demand my money back. But still, either they lied or they didn't put it back together, so I don't trust them to touch my car ever again.
In your experience which do you think is more likely? Just curious...

Thanks for the info on the sensor, I will try cleaning it out only as a last resort before replacing the hub.

OBD reader should be here tonight.
They may have been rushed and forgot to tighten the bolt up after diagnosing it. Some vehicles you can easily access the sensor without removing the wheel, with the car in the air.
 

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Discussion Starter #10 (Edited)
Okay, it's not the sensor.
There happens to be a hole in the plastic splash guard (not sure what it's called) under the car, right next to where the connector is and there is wiring exposed. Is the ABS control module accessible so that I can test the wires for continuity? I can't find a diagram anywhere.


UPDATE: Replaced the hub and it was indeed the problem. All is good now :D
 

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