My Check Engine light is turning on & off intermittently (5 days on / 1 day off for example) but there's no malfuction codes stored in the ECU. I can clear/reset the Check Engine light with my generic scantool but the CEL will come on again after a couple of days.

What could be the problem? because the car run fine otherwise.

Thanks
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Norm

In theory, the CEL can only come on if there is a code thrown. No codes, no CEL. I would suspect your problem is the scanner not being able to report properly. Have it verified at an Autozone when the CEL is on.

Klaus
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1975 164 w/174,800mi (Sold) 1995 850T w/91,000mi, 1998 V70R w/129,000mi

Thx Klaus,

I've already tried with an other generic scantool of a completly different model, same results: nothing. Someone told me that it could a "specific" Volvo malfunction code, not a generic OBDII one that I need a VADIS (Volvo Aftersale Diagnostic Information System) to be able to retrieve that specific code stored in my car ECU. I'm wondering of what kind of fault code it is because everything is fine so far with the car. Engine start quickly, fuel comsuption is low, the car accelerate well and running great. ABS, SRS, ECC, power seats, instruments group, tranny ect, everything seems to be in a good working condition. I have absolutely nothing to complain about the car. Any ideas?

Regards
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Norm

Check this out: http://www.ilexa.co.uk/content/category/2/2/2/

It's a UK based company specialized in automotive scantool software for european cars. It could be interesting for you.

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Ken

I've had an on off CEL from a loose gas cap. I've gone to check it with my scanner and the dang light would be out. I believe the code (when I finally read it) was something like evaporative system leak (small leak)

I've swapped my gas cap with my other brick, we'll see.

Thanks

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Norm

Turn your instrument lights on with the key in POS II. You may have a burned out bulb. Like SRS or ABS.
Talk to your local dealer and see if he will overcharge you to check the Volvo specific code.

Klaus
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1975 164 w/174,800mi (Sold) 1995 850T w/91,000mi, 1998 V70R w/129,000mi

I checked out all of my instrument lights and I have no burned out bulbs. Is there a meaning of a flashing check engine light? is it for an emergency? because my CEL started to flash this morning. The CEL is supposedly to be steady on but now is flashing. Two things one: My ECU is really sick and there's no real problem with the car or this is a real emergency problem and I'm urged to fix it. All hints are welcome !
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Norm

No answer to your flashing CEL. Check the fluid levels in the engine bay, all of them. If you have a voltmeter, check the alternator output for 14volts+-. Recheck the vacuum lines for any cracks or leaks.

Klaus
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1975 164 w/174,800mi (Sold) 1995 850T w/91,000mi, 1998 V70R w/129,000mi

Yes a flashing CEL! Unbeleivable heh?
The alternator voltage is fine at 14.1 Volts. The vacuum lines and elbows are all fine too, I've replaced all of them last august. I think my ECU went "crazy" for somehow so for a last remedy, I've disconnected the battery overnight and the car seems to be fine since. No CEL for the last 2 days. I'm keeping my fingers crossed. Thanks.
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Norm