So as a follow-up to my previous posts my drama continues. As a summary my issue is that upon cold starts my 01 outback wagon hesitates and at times shuts off, but once warmed up it runs fine, some board members thought that it might be the coolant sensor, btw car throws no codes out.

 

So I take the car to my local soobie dealer and they give me a estimated bill of $1300 bucks, among other things they tell me I need to reprogram my ECM, which I didn't understand. I tell them to hold off.

 

So this morning I go to pick up my vehicle and it's running even worse, the hesitation continues even once the car is warmed up now and still no CEL. I read the mechanic's notes on my estimated bill and it states the following:

 

"performed EEC system test and retrieved code P0031 for 02 sensor and ECM re-program"

 

So my question is what is a EEC system test and how did the dealer retrieve a code when my OBD II scanner did not and there is no CEL on? Also can a o2 sensor be a culprit for the cars hesitation and if so why no CEL?

 

Sorry for my posts but I am not only trying to solve my problem but I want to learn about it as well. Thanks in advance guys.

For now I would ignore the O2 sensor codes.

 

I would disconnect the battery to reset the ECU since you now have all codes read.

 

Drive another car to the dealer and buy a Coolant Temperature Sensor, go back to the car and replace it, then reconnect the battery and see if you still have the hesitation problem.

 

This is the easiest (cheapest) way to start eliminating any possible problem and in my opinion the best place to start.

 

Just my 2 cents.