Fault codes
 

My 2.5 V6 has been diagnosed with fault codes p0481 and p0304 which the garage described as cooling fan relay high speed fault and misfire detected cylinder 3.
However I am now wondering if their description for the misfire is correct as we have replaced coil and spark plug on cylinder 3 with no improvement.
I read an earlier thread which gave p0304 as cylinder 4 on the rear bank.
Could the brains trust comment, I am confused.

Yes you're right it's misfire on cylinder 4

Thanks Steve. Is the cooling fan high speed fault p0481 an indication that the silver resistor has failed and should be replaced with the gold one.

No John, I'm afraid that your garage has got that one wrong as well!

P0481 relates to the medium speed on a 3 speed system. If your car has just 2 speeds with the resistor, the diagnostic equipment thinks there's a fault with the medium speed because it cannot trigger it. That is, of course, because there's no medium speed on a 2 speed system.

The silver resistor is in the low speed circuit. You can test that yourself by selecting the windscreen demist function with the engine running (from a cold start preferably) and checking that the radiator fan is running continuously.

Good luck with cylinder 4!

Simon

If the fan has not been replaced then your early car would have had the 3sp fan type. If it's only the high speed that has failed, which in my experience is unusual, then you should still have low & medium. But we are guessing, do Simon's test and verify that at least slow speed is working, then get yourself a copy of Toaf and the cheap lead and you can test all fan speeds yourself (and a lot of other stuff including misfires), without having a garage mis-diagnose things.

Regards

Great advice from Simon and Vitesse, really appreciated. The car is a 2005 2.5 V6 so only two speed cooling fan, I will carry out the test suggested by Simon.
A question “what or who is Toaf”
I am trying to remove the coil and plug for no 4 cylinder, what a p...k of a job. May end up removing the inlet manifold!!

OK a later car then, I went by the year of the one in your profile.

Toaf, in short = a kind of mobile T4 or alternative, free to use programme requires a cheap KKL lead, use the search facility for more info.

Go ahead and remove the upper inlet manifold, so much better access, change all rear spark plugs at the same time. I recommend removing the manifold as there is an earth lead going to one of the rear coils, if you can't see it and remove it by mistake and then start the car there's a real risk of damaging the cars main ECU (EMU).

Regards

ps There are two hidden brackets supporting the back of the manifold which you've got to remove

Hello, i have the same.problem : code P0481. My cooling fan works when i test it by selecting the windscreen demist function with the engine running(the climate works well).
It's a later 2 fan speed with silver resistor ( i think it's not the originat cooling fan).
What do you think ? How to test the high speed ?
Thanks you guys.

You haven't got a problem Brahim. See my post no. 4. Please let me know if you need a fuller explanation.

Simon

Thanks you Simon.
But is it possible to test the high speed?