05 WRX Engine Warning Light
05 WRX Engine Warning Light
Author
Discussion

markcp

Original Poster:

245 posts

267 months

Monday 2nd November 2009
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My wife was driving our 05WRX PPP yesterday when the engine warning light started flashing. The car still drove ok and didn't initially show any signs of a problem.

Just to make sure we called the AA out ansd when he plugged in his laptop to the OBD it showed a problem on cylinder nr 2. Otherwise all looked ok in the engine bay so he cleared the fault on the laptop and it was then fine, including a spirited test drive.

Does anyone have any suggestions as to the cause of the problem that would have caused the ECU to put one cylinder into safety mode?

Thanks,

Mark.

ScoobieWRX

4,863 posts

250 months

Monday 2nd November 2009
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Doesn't put one cylinder into safety mode, limp mode affects all cylinders (The whole engine).

I'm willing to bet the ECU recorded a misfire if the code the AA man detected was P0302 which is a misfire on cylinder No.2. WRX's do that sometimes and it may just be a rogue event, something and nothing but worth checking the spark plug and coil pack for cylinder 2. If it does it again it will be one or the other.



Edited by ScoobieWRX on Monday 2nd November 17:53

Automental

219 posts

225 months

Tuesday 3rd November 2009
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Mine does that sometimes for no obvious reason and drives fine. I'm usually able to reset it by switching engine on and off 3 times. Can't remember where I heard that trick!

markcp

Original Poster:

245 posts

267 months

Friday 5th February 2010
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Excuse my ignorance, but can someone tell me how to reset the ecu?

Thanks.

ScoobieWRX

4,863 posts

250 months

Friday 5th February 2010
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On a newage the only way to reset the ECU is to connect a laptop with diagnostic software and appropriate cable or hand held diagnostic device to the OBDII port.

Otherwise you would have to leave the battery disconnected for the best part of one to two weeks.

Turning your ignition key off and on three times is a load of old cobblers. Whoever told Automental to do that is having a laugh with him. The misfire code goes away by itself after a while but will stay in the ECU's history until the next reset to show whoever takes a look what trouble codes have been generated in the past. A reset will also reset the ECU's DTC history. wink

Edited by ScoobieWRX on Friday 5th February 23:21

markcp

Original Poster:

245 posts

267 months

Saturday 6th February 2010
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Bugger frown The AA guy reckons its a failed coil pack and couldn't change it so it needs to go into the garage...

ScoobieWRX

4,863 posts

250 months

Saturday 6th February 2010
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And it could just be a spark plug. If the coil pack was faulty then more than likely it would misfire regularly across most of the rev range, same for a buggered spark plug, and specially under load.

WRX's are prone to throwing up misfire and Cam Postiion Sensor codes even though there is nothing wrong with either.

Change the spark plug first as it will be a lot cheaper than a coil pack. Don't go lashing out money if you don't have to.