Why did my CEL light come on?
 

Can anyone give a suggestion as to the cause of this....

Owned MY01 WRX Bugeye, 70,000 miles with absolutely no problems at all, excellent car. At the moment the car is completely standard other than K&N Panel filter installed about 1 month ago. After reading all the generally positive reviews on Tesco Momentum 99 I decided to give that a go.
All good, didn’t notice a huge performance gain if any but I’ll stick with it. While driving last night, about halfway through my second tank of Momentum, all of a sudden my CEL light illuminated, I wasn’t thrashing the car, just pottering along normally. It blinked on and off for about 10 seconds then disappeared. The engine appeared fine, no stutter, misfire, idle problems etc and it ran as normal. I drove for about another 5 miles before leaving the car at home. I’ll see how I get on today.
Is this pure co-incidence or could a change of fuel cause the CEL to light? I read in my manual that a flashing CEL might just go away itself and it was probably a problem with an emissions related sensor. I think you need to start worrying more if the light stays on for good. Has anyone else had this problem or could someone suggest the cause of it? Obviously I could plug into and OBD check but I don’t have one of those to hand!
Suggestions appreciated.
Marc.

Hi Marc,

It's hard to say. The CEL could have popped up for any reason.
What is your location? Maybe someone close to you willing to plug in a CEL reader?

I would however have to mention that I have heard on here and a few others that the Tesco fuel is causing a few stirs at the moment.

I've switched back to V-power as I noticed the MPG was shocking if using Tesco. Only bonus was the clubcard points.

Steve

Hi, I'm Windsor/Slough area of Berkshire. I've just been for a drive and No light so that's something. I won't worry too much about it for now.
Yeah I agree about Tesco, it's certainly not worse than V-Power or Ultimate for performance but I'm with you on the economy - about the same, maybe a bit worse but 60 quids worth of Club Card Points is always worth it for me!

Dodgy tesco fuel for your clubpoints i like your style. v-power all the way owned a classic for years and only ever used v-power runnin 340bhp and not had any probs on a 12 year old car. will be close to 400 bhp tomorrow after map tweak, so we will see how we get on after that. i must be getting close to the limit on standard classic sti internals...

Marky,

Was the tank almost bone dry before filling up etc? Possbile some crud sucked up and tripped the ECU.
Has the car been modified at all? Filter,pumper change etc.

Is the car a Euro/UK spec WRX or Jap/USDM/ASDM model? Is so happens I am close-ish to you and work in Slough/Colnbrook. If you need me to plug my thing in (pardon the pun) let me know by PM and we can meet up quick to check.

Steve

had this on mine a while ago then got worse and worse (means engine misfire detected)
ended up replacing the front oxygen sensor and this fixed it. always run my bug on tesco 99 had no problems

Steve,

Yeah spot on, the tank was very empty, in fact probably the lowest I've ever let it run so your diagnosis is probably right. Cheers for the offer - I'll keep an eye on it for a week or so and then let you know. I presume I haven't done any damage to the engine? It still runs fine, or at least seems to.

The car is UK Subaru Dealer Spec 2001 with no mods other than a K&N. Hopefully getting my new de-cat exhaust fitted this week. And there's a whole new story on CEL's there!

Marc.

if ya get a cel fix it will stop the cat deficient CEL coming on but i would recomend you get a remap if your getting a decat as it causes over boost and a very jerky ride

Hey Marky,

I would have thought the car didn't like being ran so low on the fuel to be honest but who knows? Just keep an eye on it. Happy to meet you as previously suggested if needed.

As Pinkypurkhardt has stated above. Juat mind how you go on the de-cat. Running de-cat WILL bring up the CEL light as the ECU will read "No CAT" and bring up error code 420(I think thats the code?)
To make the most of the de-cat and taking into account of what else you want to do I would maybe upgrade the map on the ECU. Not cheap but only the best way to make the most of the De-Cat pipe. You MAY still get away with Co2 come MOT time if you keep the up-pipe cat in place but not 100% sure.

I'm using a Sports Cat on my car with other mods at 453bhp (2002 STi) so haven't gone de-cat route. If your thinking of upping the power, I'd get a centre de-cat, new fuel pump Walbro 255,remap the ECU and jobs a good'un.

Spend the extra cash on brakes,handling if required but dont get a dump valve. Complete waste of time.

It's your car and your money mate but just given you a bit of sound advice.

Steve

The De-cat CEL is P0420 :) and will come on if you de-cat !

Your Denso ECU was / is an amazing leap of technology from the old Classic JECS ECU but the technology came at a price in that it got confused at high revs (and threw camshaft position error CELS) and it also got confused with the neutral postion switch on the gearbox and flashed misfire CELS !!

Re-mapping de-cats is bread and butter for someone like Duncan at Racedynamix....More torque / BHP / driveability.

http://www.racedynamix.com/new/

The same can be done wityh an EcuTec Remap but for your needs a cheaper option is very pragmatic :D

Shaun

My standard MY01 WRX Bugeye has light blinking or staying on at regular intervals - normally code P0303 misfire on cylinder 3, which may also be linked to fault with Neutral Position Switch. CEL blinks or comes on when I'm accellerating a bit harder and chnaging from 3rd to 4th. I have even had CEL light stay on for a week or two then it magically clears itself which is wierd. Some say this is a typical Bugeye thing a bit like the occasional clutch judder panic which then also goes away.

have your air/fuel ratios checked mate sounds similar to what i had, i had a p0136 aswell and all the misfire codes in the end which turned out to be oxygen sensors but could be the neutral position switch aswell the joys of owning scooby eh lol

Cheers folks, all very helpful. CEL has not returned so I'll stop holding my breath! Yep, I want a remap but 1) need to save up and 2) need to convince the Mrs. 2) is a lot harder than 1)....

Shaun wento into it with a bit more depth. :thumb:

Marky, know the feeling mate. I had to tell a few white lies to my other half over the last 6 months about how much this and that was costing on the car. She'll find out one day I am sure. :(

Why don't you built up over a period of time the bits you want to add then add them at the same time including the map? Will feel like a new car.

Steve

ha ha ha i know the feeling took me ages to get the good ahead for the remap "what does it cost that much for i hate that stupid car" lol she rather spnd it on bags or the kids:cuckoo: lol i just tell her stuff is broke and i need a new 1 ha ha ha