ECM box fan test in VIDA?

Pivo · Post by **Pivo** » 17 Mar 2025, 13:05

Hello! It's been a very long time since I posted here, as I had seven years of loyal, relatively trouble-free service out of my 2003 XC70. But I recently scrapped this car in an accident, so I now have a 2006 XC 70 that' s driving me nuts... There's a lot of trouble with what seems to be communication errors that only happen in milld weather that take the BCM, TCM, etc.

Right now I'm trying to figure out if the fan that cools the ECM box works as it should. I know the fan works as I took it out of the car and tested it with a 12V power supply. What I'm trying to check is if the control circuit is working allright... I'd like to know if somewhere in VIDA is an "activation" function that can "activate" this fan...
thanks,
Pierre

Pivo · Post by **Pivo** » 17 Mar 2025, 13:06

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Post by **jonesg** » 19 Mar 2025, 02:21

I don't know the vida answer but had trouble with that little fan,
I had checked the fuses but placed the ecm fan fuse back in the wrong slot so it didn't turn on, on a hot day after a good run it started throwing codes faster than I could read them, everything from rear window wipers to headlights, probably 20+ codes.
So if it isn't working you'd know it, everything goes haywire.

It might be possible in vida, look in ECM activations menu.
I know a poor wheel abs sensor can cause TCM problems, like a failsafe mode.

Pivo · Post by **Pivo** » 19 Mar 2025, 06:26

Thanks for the reply!
The inquiry is still on, it has made "some" progress: I have read somewhere, perhaps in VIDA, that the fan can be activated in VIDA... If so, I still haven't found where. What I found in VIDA is that the ECM detects and monitors the fan, and has a selection of codes related to it. And that is true, as I got a code when I disconnected the negative wire of the fan to tie it to chassis ground. That makes the fan run continuously when the ignition is on. I'll leave it like that for a while, see if it does anything for my condition. I understrand pulling the fuse wreaked havok for you as this fuse, according to my manual, also provides power to AC compressor and the accelerator pedal position sensor...

Post by **jonesg** » 19 Mar 2025, 11:47

I'm sure the ECM switches the fan, either by monitoring the coolant temp or its own onboard heat sensor.
I think you're barking up the wrong tree, unless the car is going code crazy, the ecm fan is fine.

Pivo · Post by **Pivo** » 19 Mar 2025, 13:34

I too am certain at this stage that the ECM manages this fan. The thing that bugs me is I have no way to actually test this fan-switching circuit... I was led there by this thread, which covers a similar situation of alerts thrown in certain temperature/humidity conditions viewtopic.php?t=62816 . Be sure to read the end of this thread, it's enlightening! I spent the better part of yesterday fashioning an ECM removal tool, and today I successfully removed the ECM. I have seen what appears like a good deal of green corrosion on the connector... I sprayed it with De-oxyt. did the same with the TCM. I also restored the ground connection to the ECM box fan. Tomorrow I have a little trip to take: if I can get back without the BCM and TCM going SNAFU I'll be very happy. Otherwise I'll have to attack the CEM.

Post by **jonesg** » 20 Mar 2025, 10:17

ha ! the green gremlins.

Pivo · Post by **Pivo** » 21 Mar 2025, 06:51

My little outing has been postponed, so I can't tell for the moment if my actions have cured my problem. What I can say now is the "antenna ring" appears quite interchangeable between MY of the XC70: I have transplanted the one from my 2001 parts donor car in this 2006, and my code for said antenna ring has dissapeared!

Pivo · Post by **Pivo** » 22 Mar 2025, 16:30

I' just back from my little 65 KM ride: no ABS panic messages nor transmission misbehavin' . I'm quietly shouting victory... time will tell, but I'd say it's another testimony for the De-Oxyt treatment...

Post by **DavidE7** » 25 Mar 2025, 22:11

Does your air conditioner work? try running it on full blast next time you drive to see if the cold air helps prevent error codes. The tube connected to the fan goes to the HVAC...