[Bmason777]

So ive dealt with plenty of speed sensors, but when it comes to wires.... anyways, my 2012 chevy volt is throwing the front left wheel speed sensor code, c1225. I have changed out the sensor, and flashed the codes but the c1225 pops back up with .5 miles. Anyone have any ideas or experience on what to try next? I can't find a layout of the wiring anywhere and it gets pretty tough to trace the wire into the bundle of mess going to the abs unit.

Thanks in advance!!!

 

[NANORDU]

You don't want to know how much trouble I have had with the wire bundle (High Speed Data Buss). It either has 16 or 18 connections to various sensors. My 2012 has been in the shop twice, 1st time 6 weeks for them to find problem, second time, 4 weeks different dealer. I had to call VOLT help line to get the dealers help on how to trouble shoot. Neither time under warranty, over $1,000 total. I talked to both techs, they say cable was manufactured with too tight of connections, unable to flex, as a result connections break and require adding a splice to lengthen wire. Both breaks on different sensor. Too difficult to replace cable, so repair was only option.

 

[Bmason777]

So I think a dirty tone ring may be the issue... thoughts??

 

[Jeff N]

So I think a dirty tone ring may be the issue... thoughts??

According to the service manual, C1225 is commonly caused by the following issues:

1. Incorrectly mounted wheel speed sensor
2. Water intrusion in the wiring harness
3. Debris on the wheel speed sensor or the tone ring
4. Missing tooth or teeth on the wheel speed sensor tone ring
5. The tone ring may be demagnetized
6. Air gap between the wheel speed sensor and the tone ring may be too large
7. Electrical magnetic interference with the wheel speed sensor harness

Your photo seems to provide evidence for item #3.

 

[russella]

BMason, your timing is impeccable. Or maybe Chevy's timing is. About a month ago on my MY2012, threw C1226 (passenger side front wheel excessive speed variation) as well as the stabilitrak/ABS instrument lights. I changed the sensor myself because cost was low, no help. Finally had my shop check the tone ring...it had disintegrated, with a couple sections of the plastic/magnet ring surface completely gone. They replaced the hub, which fixed the problem.

All was well for literally 180 miles and 2 weeks. Then same instrument lights, but this time C1225 (for the driver side). Back to the shop and they replaced the driver hub as well. The tone ring on the driver side was pretty much gone completely.

I'm planning to start a new thread on this with pictures of my hubs...if it's very wide spread for gen1 volts approaching 66 months or 100k miles in service then perhaps the design had a weak point where slow corrosion was essentially inevitable.

I see from your other thread on the HV pack that you also have a 2012. I wonder what part of the country you live in? Do you know when your volt was put in service?

-russella

 

[NYvolt21]

BMason, your timing is impeccable. Or maybe Chevy's timing is. About a month ago on my MY2012, threw C1226 (passenger side front wheel excessive speed variation) as well as the stabilitrak/ABS instrument lights. I changed the sensor myself because cost was low, no help. Finally had my shop check the tone ring...it had disintegrated, with a couple sections of the plastic/magnet ring surface completely gone. They replaced the hub, which fixed the problem.

All was well for literally 180 miles and 2 weeks. Then same instrument lights, but this time C1225 (for the driver side). Back to the shop and they replaced the driver hub as well. The tone ring on the driver side was pretty much gone completely.

I'm planning to start a new thread on this with pictures of my hubs...if it's very wide spread for gen1 volts approaching 66 months or 100k miles in service then perhaps the design had a weak point where slow corrosion was essentially inevitable.

I see from your other thread on the HV pack that you also have a 2012. I wonder what part of the country you live in? Do you know when your volt was put in service?

-russella

Same issue with mines, was driving and suddenly got the stabilitrak\abs MIL message yesterday 8/18/18 - 2012 Volt @ 79k miles, going to try swapping out the speed sensor myself, if that doesn't work I'll take it to the shop to swap out the wheel bearing. ODB codes point to an open circuit driver side speed sensor.

 

[NYvolt21]

Turns out for me it was the speed sensor, not sure how but it must have at some point rubbed against the spinning axle boots, the cable shield wore out and there was some exposed copper for some time that had turned green. I looked thru and don't see how it could've happened, the wire was properly routed attached properly with the clips. I swapped it out with a new one ($19 bucks at autozone) issue resolved car stopped complaining. View attachment 155235

 

[EvertonP]

Just happened to me as well. 2012 Volt with 103k miles.
Will check it out tomorrow, hopefully the issue will be obvious when I see it.

 

[ilusnforc]

I also got a code C1226 at around 86K miles after replacing the front passenger side axle (leaking boot) so I suspect the sensor wiring may have been damaged while changing the axle. Picked up a replacement sensor from the dealer and tried swapping it out today only to realize I got the wrong sensor and everything is closed today. I'll pick up the right sensor tomorrow if the dealer has it and if that doesn't fix it I'll be ordering a replacement hub. I'm really hoping it's just the sensor.

 

[biggamehunterto]

Just had a C1225 set after hitting pot hole in the road. Ordered a hub and then went to replace. When I removed the hub I found a broken washer between the job and axle shaft. Called local dealer and they had it in stock for $4.00. Went and picked it up , not going to let a $4.00 part make me do a job twice.

Cleared codes and all is working now. Just wondering if the speed sensor was seeing that broken washer?


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[ilusnforc]

Replacing the sensor has not yet resolved the issue. I don't have a tool to clear codes so I don't know if it's just a matter of clearing the C1226 code or if it should just go away on it's own if the issue has been resolved, but I'm under the impression it should go away on it's own.

I'm starting to think that the issue must be the magnetic tone ring on the hub, either has debris or is damaged/falling apart. Thinking back when the axle was replaced and the ABS issue followed shortly after, the person that put the axle on forgot to put a small part on that looks (and about the same placement) a lot like that washer and didn't want to take it all apart again to put it back on and they were very certain it served no purpose. Now they can't find it. I'm wondering if perhaps it's purpose is to keep debris off of the magnetic tone ring on the hub?

I have an appointment to get it diagnosed tomorrow, I'll definitely have them look for this.

 

[biggamehunterto]

When I replaced the wheel bearing/hub there was no tone ring that could be seen.Sealed hub. When I pulled the hub I found the broken washer. Refer to my 1st post for part number. Dealer part only and it was under $ 4 and in stock at my local Chevy dealership. You might want to go pick one up.


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