Hi all, there's advice about P0481 issues all over the internet, but nothing seems to be quite what I'm experiencing.
It's a 2014 2.2 Citroen Relay on 63,000 miles. I've owned it for about 8 months, and until now have had no issues.
3 weeks ago I drove it to work in the morning, no problems. Went to drive home, check engine light and limp mode immediately upon startup. I had the AA look at it the following morning while I made my way to work, he told me it was a P0481 but not in limp mode for him, he checked all the relays and fuses, couldn't find the issue, and cleared the fault (it then stayed clear and out of limp mode). I then took it to my local garage, they had a look but recommended I took it to an auto electrician. A few days later it went back into check engine and limp mode, I was able to clear it myself and get home. The following day it went back into limp mode again, this time I was unable to clear it. I took it to a highly recommended local auto elec. with a very good reputation. He plugged the van in, and using his diag. equip. he was able to have the ECU actuate the vans, and the fans would work. But one fan struggled to run, and was much slower than the other when it did manage to run. He did a few more tests and confirmed the fan was faulty.
I took the van home, removed the faulty fan, bench tested it and confirmed it was faulty. Ordered a new one, bench tested it, confirmed it was good. Fitted it but still had the fault. I then checked all the wiring, relays, fuses, everything was good. When I supplied an earth to the low current switch side of relay T07, as I believe the ECU should do, the fan ran fine. This proves the circuit is good from the fusebox to the fans.
Took it back to the auto elec. He found there were two connections together from the earth side to trigger the relay, when there should only be one from the ECU. And suspected that the current drain trying to make the faulty fan work had melted a connection in the fusebox, joining two connections for the low voltage side of the relay. He suggested trying a new fusebox. So I've replaced the fusebox and STILL have the fault.
It's now been 3 weeks and is a nightmare, made worse by the lockdown restrictions.
The fan is good, the fusebox is good, the relays and fuses are all good, and the wiring is all good. This only leaves the ECU. However, if the ECU was at fault, surely the auto elec. would not have been able to have it actuate the fans?
Does anybody have any ideas? I'm now completely lost with this.
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