MY02 WRX only mod is backbox. 55000 miles.

CEL came on before Xmas, diagnosed as misfire cylinder 1. New spark plugs, reset.

CEL came on again 1 week later.

Assuming that it's the same error code, what is the next step in diagnosing the underlying fault?

 

Speedking,

Common fault with the bugeyes I'm affraid.

There has been a few threads on SN over recent years. Try doing a search on Neutral Position Switch.

Cheers

Martin

 

Thanks for that. Looks a possibility.

Think I'll try a new Neutral Position switch. Got to be worth a try rather than having the engine stripped down, which was the dealers first suggestion for diagnostics, before I suggested changing the spark plugs! He could also hear the misfire

How much is a new switch? Is it a straightforward DIY job i.e. no specialist tools, nothing to line up requiring three hands?

 

Just been to System-R who read the error codes which showed misfire on cylinders 1, 3, and 4, despite the car starting and running fine Will try the Neutral Position Switch and see if that cures it.

 

Purchased a new neutral position switch. £31+

Replaced switch ~1 hour and 10 minutes. Including half an hour trying to work out how to undo the front clips on the gearbox tray, and half an hour undoing the connector.

Have driven two days now, deliberately provoking the engine and simulating the conditions when CEL used to come on, not a flicker

I am staggered that a faulty neutral switch causes spurious misfire error codes. The end of the plastic plunger was worn from a dome to a slight chamfer, say 0.5-1 mm at most.

Fantastic diagnosis and no doubt saved me a fortune. Well done Ninnybobs and Scoobynet

 

it's the cause of a few problems is the neutral switch and your dealer should have known about it. it's easy to spot on the select moniter so i'd find another dealer really

 

speedking,

Did it fix it? I'm curious having lived with the CEL on now for nearly 2 years If it works I'd prepared to shell out a few quid to fix

 

Living with the CEL on for 2 yrs - god ur a brave boy !!

I've owned a fair few cars in my time from fords to alfa's and I've never known any manufacturer who you hear has recommended the engine to be stripped to diagnose a problem as much as subaru do. I knew I should have bought a Golf VR6 lol

 

Well I had a Corrado VR6 a few years ago and it was THE most unreliable car I ever had, so rest easy !

BTW the first year was the worst, after that you just learn to ignore it

 

@ Nigel H: 4 weeks on now and no sign of the CEL. I haven't had the codes cleared but I think they clear themselves after a while. I have tried to 'provoke' the error by chugging up sliproads and cannot get the light to come on, therefore I reckon its definitely cured.

If you don't want to risk the £30 cost of the new switch you could unscrew the old one and inspect the end of the plunger. Mine was worn and you would be able to see if that is a possible cause. Of course you wouldn't then be able to drive to the dealer to get a new one

Have you had the codes cleared and then noted the conditions when the CEL comes on?

Good luck.

 

Yes had the codes checked by Xtreme Scoobies. It's always misfire on cyl 1, so to start with I changed coil pack and all spark plugs, this made no difference Chased a few other things but to no avail, so I gave up, and two years later I'm no worse off

Given that it's only £30 I might change it next time the car goes for a service, it's worth a punt 'cos having the light on still bugs me!

BTW symptoms - mainly on the motorway when going up long hills at speed , but it's become more regular and now happens even on local roads. I've tried changing gear when the light is flashing as I was aware that this was a possible cause in the hope that this would stop it. But it didn't

 

My typical scenario was to be travelling in lane 1 in slow traffic and then peel off onto a rising sliproad, accelerating from 50 to 7x in 5th gear. I believe that the light will flash on the first occurence, and then stay illuminated if the same fault occurs on the next journey. HTH.

 

speedking,

Sounds similar enough to me. Thanx for the advice

 

I've now had a new switch fitted (cheers Knowlsey!) and my CEL has been out for 3 weeks

Thanks speedking and scoobyboy for the advice

 

The dealers always suggest this, bloody ridiculous.

 

Had missfire code on mine recently, turned out the fuel pump was on its way out.