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16th March 2021, 00:22 | #1 |
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1999 Rover 75 2.5 Connoisseur saloon Join Date: May 2007
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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.
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16th March 2021, 03:58 | #2 |
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Yes you're right it's misfire on cylinder 4
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17th March 2021, 05:00 | #3 |
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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.
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17th March 2021, 07:08 | #4 | |
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Quote:
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
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17th March 2021, 09:07 | #5 |
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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.
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18th March 2021, 01:44 | #6 |
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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!!
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