Codes,codes, and more codes
 

The other night I finally ran the diagnostics on my '95 L after an intermittent CEL. To my dismay it popped up four codes: both O2, Water Temp Sensor, and code 56 (EGR). I already ordered O2 sensors and wasn't sure what to do about the others.

I was reading another thread and heard that there were two different Water Temperature sensors?? How do I know which one I need? If it is the one that is only $20 on subaruparts.com I will be very happy.

The other question I had was about the EGR system. What other kinds of tests can I run to pinpoint the problem?

Thanks,
Collin

Re: Codes,codes, and more codes
 

Collin,
I'd simply replace the O2 Sensors and go from there. Sometimes, the O2 Sensors will trigger multiple codes. When mine were going bad, I not only got the O2 code, but, a crank angle sensor code. Once the O2 Sensor problem was straightened out, the crank angle code went away also.

Once the O2's are in, re-set the diag and drive it for a while to see if you receive any of the other codes. My guess is that some, or all of them, may go away. But, that's just me. :)

I was recently getting an EGR (56) code along with a code 11 and 21. The dealer replaced the coolant sensor (the code 21) and it fixed the 21 and 56 codes. He said that the EGR fault commonly gets tripped due to other problems. In your case, probably by the water temp sensor. I would replace that and reset the codes to see if the 56 code comes up again.

If the 56 is the only code, it is probably because of a vacuum leak. Check all the hoses to make sure they are nice and tight (follow the vacuum diagram under the hood).

My code 11 is being caused by bad battery cables. I have had a new set on backorder from 1stsubaruparts.com for two weeks now. Grrrr.

Matt

I can't stress enough about resetting the ECU or clearing the codes before believing what comes out.

The brains on our car remember faults for as long as wives do... ;) :D (runs for flame suit)

Once you clear the codes, wait until the next time the check engine light comes on, and then pull the code. Otherwise, you may be replacing parts that are in need of fixing.

Symptoms should match the code as well. i.e. if you are getting O2 sensors, and getting poor mileage, that makes sense. If you're getting water temperature sensor fault, you should see irregular idle or other possibly other engine performance symptoms.

VK

Thanks for all the input.

I already reset the codes last night and I hope they don't come up. If they do I already ordered O2 sensors and will start with that. I figure going on 100k O2 sensors are likely to go.

The weird part about all of this is that I have never had any symptoms. I have cleared the ECU before (never pulled codes) and the GD (CE) light has come on after that. I just don't want anything to become bigger than it is. Oh well, we will see.