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2003 Forester: CEL but no code

Hi all,

About 2.5 weeks/300 miles ago my '03 Forester (US) started showing a check engine light. I hooked up my OBDII code reader and when I read the display, there was not code recorded. I thought that maybe there was some noise in the system, so I used the code reader to clear the CEL, which it did. Shortly after I started the car the next day, the CEL came back again with no code recorded. I've started leaving my code reader connected while I'm driving to see if it can pick up a transient code, but nothing has been recorded. Some other things to note:

- the car runs great and my fuel mileage is normal

- when I reset the CEL, the I/M readiness monitors were also reset. In the two weeks or so since then, the oxygen sensor, catalyst and evaporative system monitors have yet to come ready

- don't know if it matters, but about 6 weeks ago, I had the pistons replaced under warranty for piston slap. At the same time, they replaced the cam belt tensioner, cam belt and various seals.

I've done some googling about this, but everything I've found (none of it Subaru specific) was basically "your computer is fried, buy a new one". It seems to me that if the computer was actually gone, the car wouldn't run normally.

Advance for any assistance...

- Snuffy -

-- Feeding the trolls since 1989.

Reply to
Mike Bender
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Anytime there is a code, it should be recorded. Maybe there is something wrong with your code reader. Hopefully its set to read both active codes and codes stored in history!?

CL

Reply to
dnoyeB

Yep, very curious. Has this reader worked before on your car? Any chance the reader could be tested on another sube? I THINK, there are 4 protocols for OBDII and the reader must read the ISO/w'ever style to read a sube. I think a few cheaper readers won't read subes - but then it seems unlikely it could clear the computer. weird.

I think it takes a number of heat up/cool down drive cycles to acheive 'readiness'. If you drove only short distances, perhaps that's why the readiness hasn't completed?

Carl

Reply to
Carl 1 Lucky Texan

Carl 1 Lucky Texan wrote in news:CwK%j.2314$ snipped-for-privacy@flpi144.ffdc.sbc.com:

Yup, I've used this reader before on my Subaru to diagnose an intermittent misfire due to a defective coil pack that was eventually replaced under warranty about 3 years ago. I also use this reader on my wife's Hyundai with no problems.

The driving I did after I reset the computer was a combination of city/expressway for about 10 days with most trips being my 20 minute commute with speeds up to ~60 mph, and some longer trips (about 45-60 minutes) at least one of which was about 20-30 minutes on an interstate. This kind of a driving pattern in the past has been enough to bring the monitors to readiness. I'm really puzzled by this and I really don't want to go visit the wallet-vac at the Subaru dealership. Luckily my emissions inspection was just last month so I've got nearly a year to figure this out.

- Snuffy -

-- Feeding the trolls since 1989.

Reply to
Mike Bender

WEll, I think it may be time to find an Autozone or 'friendly mechanic' to see if their reader can get a code. I'd say there could be merit to the 'fried computer' (at least the scanner interface port) IF a different reader fails in a similar manner.

good luck

Carl

Reply to
Carl 1 Lucky Texan

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