Check Engine

Author
Discussion

5paul5

Original Poster:

664 posts

177 months

Friday 25th January 2013
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Bought a classic wagon turbo today, on the drive home the check engine light flashed on and off briefly a few times,car drove fine otherwise, am i looking at any potential problems, any ideas anyone ? Thanks.

5paul5

Original Poster:

664 posts

177 months

Friday 25th January 2013
quotequote all
Just noticed the other thread on this subject, different model but i suppose the same applies.

ScoobieWRX

4,863 posts

232 months

Friday 25th January 2013
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Newage WRX's do this too after a cruise on the motorway. Could be momentary glitch with the Lambda sensor, or cam sensor, or MAF sensor. You can't do a lot with the CAM sensor apart from change it but you can clean your MAF sensor out and just check both front and rear Lambda sensors have no loose connectors, dodgy wires and aren't damaged.

Sometimes after a motorway run, because the car runs as lean as it can steady state on cruise for long periods when you come off the motorway or suddenly stop/crawl in motorway traffic the ECU or a sensor throws a wobbler. Quite common.

Nothing too much to worry about until it starts to affect the way the car drives/runs. I would just reset the ECU using a cheap handheld or laptop/tablet/Smartphone based OBDII error code reader. You might find it doesn't do it again for ages or even again. If it does then do this exercise again, or if the lights don't go out it's time to spend some money, but hopefully not a lot.

5paul5

Original Poster:

664 posts

177 months

Friday 25th January 2013
quotequote all
ScoobieWRX said:
Newage WRX's do this too after a cruise on the motorway. Could be momentary glitch with the Lambda sensor, or cam sensor, or MAF sensor. You can't do a lot with the CAM sensor apart from change it but you can clean your MAF sensor out and just check both front and rear Lambda sensors have no loose connectors, dodgy wires and aren't damaged.

Sometimes after a motorway run, because the car runs as lean as it can steady state on cruise for long periods when you come off the motorway or suddenly stop/crawl in motorway traffic the ECU or a sensor throws a wobbler. Quite common.

Nothing too much to worry about until it starts to affect the way the car drives/runs. I would just reset the ECU using a cheap handheld or laptop/tablet/Smartphone based OBDII error code reader. You might find it doesn't do it again for ages or even again. If it does then do this exercise again, or if the lights don't go out it's time to spend some money, but hopefully not a lot.
Iwas stuck in traffic for a while on the motorway and it did seem to do it when it cleared and i pulled away, owned several of these cars but never seen it happen on any of them so got me a bit worried. Thanks for the advice.

ScoobieWRX

4,863 posts

232 months

Friday 25th January 2013
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You're welcome smile

JollyGrnMonster

887 posts

203 months

Saturday 26th January 2013
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Is it one original ecu or after market?

JollyGrnMonster

887 posts

203 months

Saturday 26th January 2013
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Is it one original ecu or after market?

5paul5

Original Poster:

664 posts

177 months

Saturday 26th January 2013
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Original i would think, car is totally standard.

ScoobieWRX

4,863 posts

232 months

Saturday 26th January 2013
quotequote all
When my car was still a WRX it used to happen regularly after a cruise. No matter how i mapped it these ghostly errors would still happen and go by themselves.

Some customer cars that did exactly the same so not uncommon, although not every WRX did this it has to be said.

While my car was still under warranty from the dealer they diagnosed (from error codes) a faulty CAM sensor, replaced it and it still did it so i put it down to possibly being more Lambda sensor/fuelling or plain ECU related than anything else.

The strange thing is when i rewired the car to run the STi loom and engine it all went away. Never ever happened again. Could be some odd ECU annomally.

The only real way to see what's happening is to go on a long run with the laptop plugged in and log exactly what's happening so at the point where the error occurs you're already logging and recording the error. Hopefully that will give a clue to what causes the glitch.

I don't think there's much point to a garage plugging in unless they have a rolling road and can recreate the steady state running that leads to the error. Simon might have some views/advice on that one.