This is a add to an earlier post on my 05 Legacy i,2.5,USA made,110,000.

The AWD is not working right.It has a bad 02 sensor P0420 code for 6mo or longer.So the CEL is on with the cruise light blinking.It goes off sometimes on it's own.Then will come back on after a bit.

I found something weird out about it i think.

I drove it in the snow a few weeks ago.The AWD did not work.The front right wheel would spin only.

Today we got more snow the CEL was off.The AWD worked good.I had it on some bad slick roads.Steep hills come to a dead stop pulled out didn't spin a wheel.Worked great. Later that day the CEL was back on.I thought wonder if that CEL has something to do with AWD not working.So I tried it again in the same place.AWD did not work while CEL was on.So I'm think "Is that dang light why the AWD did not working." Anyone ever heard of that happening?????

pull the CEL code again and tell us what the exact numbers are. it's possible that there might be more than one code coming and going or something like that. doesn't seem like it, but need to check.

 

i've never heard of a check engine light causing the AWD not to work, particularly an O2 sensor code. CEL for O2 code has been on in my 2002 for the past 3 years and 60,000 miles...AWD works fine.

 

the 0420 code is benign and caused by the rear O2 sensor. you can remove that sensor completely and leave the code and the car should run perfectly (just an annoying CEL!).

 

if you think it's the code - just fix it. the spacers to fix that issue are $5 on ebay and come ready to install.

or if you have an exhaust leak somewhere, might just need to fix that, leaks can trigger that code.

Edited February 12, 201214 yr by grossgary

I have had the code read many times.It's P0420(bank 1) I bought a new 02 sensor for bank 1 $147.It didn't fix it.I've had it checked many times at different places.That is the only code it reads.The history shows speed sensor at some time but not now.

This car has the cruise light to blink when the CEL is on and the cruise doesn't work when it is blinking.

I got the plug fouler to do the by pass cheet.But I'm having trouble getting them out.They are stuck and I can't get a wrench on it.So I still need to do that.I too have an 98 legacy with the CEL on and the AWD works fine.I will get the foulers in and see what happens.

its the wheel speed sensor

 

the awd system monitors wheel slip at each wheel on that car and applies braking to the "slipping" wheel via the abs/tcs. If you have an intermittent wheel speed sensor failing, it puts the awd into FWD mode only with no traction control.