I had to replace 1 of my winter tires (Blizzak WS-60) about a week ago. I called tire rack and ordered the tire planning on having it shaved. Brand new, this tire comes this a 12/32 tire depth. My other 3 had a depth of 11/32. The sales associate told me that this difference in depth was ok since it was so small and not to worry about shaving it. While driving around tonight my s-awc service light just came on. I'm going to take it to dealership first thing in the morning. Hopefully it's nothing serious. Has anyone else had any experience with this situation?

 

In theory you should not run different tire sizes as it will trigger a CEL. I would not have thought that such a small difference would cause it though!

 

I don't think it's possible to keep them all exactly the same depth. I measured all 3 old tires. 1 was 7 mm and the other 2 were 8.

When I took my Advan's off, my front passenger side tire was pretty unevenly worn. I had the car aligned earlier in the year so I was a bit surprised. I'm hoping it's something simple as an alignment. I just don't want the dealership to try to void any warranty.

 

OP: Did you do the optional reflash of the S-AWC computer? If not, then it's quite possible you just lost your hydraulic pump to the cold weather. This is an issue with 2008s.

(The idea that 11/32 vs 12/32 of tread depth could trigger a CEL made my day. Thanks.)

 

No, I haven't tried that yet. I've read a lot about the hydraulic pump but the timing seems too coincidental.

 

Well, you have a double coinkydink: tire replacement and cold snap. The thing that goes wrong on 2008s is that the pump kicks in immediately while the fluid is still very cold and the pump kills itself. The optional reflash is to delay the onset of the pump until the diffs warm up. You and I are both in places where this is suggested. In, e.g., North Dakota it's a must.

I'm sorry to add: if the light is on and my theory is correct, it's too late for the reflash ... the pump is already dead.

 

I took car to dealership and they I had them check alignment. It was off even though I just had it aligned in June. They weren't able to pull a code so they said everything is fine. So far so good.

 

Wait. You went in with the S-AWC light lit and they couldn't read the code?

 

The light would go off when I turned the car off and wouldn't go back on until about 20 minutes of driving. I guess they can't read it unless it's on. I thought there might of been a sort of "history" of codes. Apparently not.

 

Then I'd drive it to them and have them read the code before you shut the car off....

The good news is that it doesn't take a dead pump 20 minutes to throw a code, so that's probably not the issue. But you probably should find out what it is.

 

The difference of 1/32 is less than 1% rotational circumference. But in a later post you said one was 7/32 and the others were 8/32. The difference from 7/32 -- new at 12/32 is quite a bit.

But like someone said, check the fluid level for your pump, and for 08's a lot of people of posted about the the coldweather and the pump. I would check over all those things before visiting the dealership, as if you put 1 tire with 12/32 and have 3 with 7|8/32 You might have warranty claim problems.