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View Full Version : Coolant/radiator fan runs constantly


XC70forme
03-19-2010, 08:06 PM
The coolant/radiator fan starts to run as soon as I start the engine. It was doing it before for a few days, then the CEL came on. I got the codes (P0111, P2108) cleared, and the fan stopped running. Now it has started again. It winds up right at engine start up,and doesn't stop. Coolant is full. Is this a bad Coolant Temp Sensor?
kain
03-20-2010, 06:03 AM
Could be.

What are the descriptions of the codes that were thrown?
Chilled Man
03-20-2010, 09:00 PM
Change ECT and Thermostat

call the guys in my sig

01 = two seperate parts
02+ = one part
XC70forme
04-01-2010, 07:35 PM
Well, I changed the Thermostat/ECT. The fluid was very new so I re-used that. My question is- Should the fan/CEL turn off after the install, or is it normal that I had to clear the code (P0111- Intake air temp sensor 1 circuit range/performance) to make the fan stop and CEL turn off? I am worried about it recurring.
Willy
04-02-2010, 09:12 AM
Doesn't the fan assembly also contain the electronics that drive it as well?
I seem to remember this can fail, I also think this could mean the whole assembly has to be replaced :(
Should you think that this might be the problem, perhaps you could find the connector to the fan assembly
and disconnect it. If the fan stops, the problem lies elsewhere. But if the fan continues to run......
Willy
Willy
04-03-2010, 12:28 AM
In the mean time, I took a closer look at the schematics.
As can be seen from the pdf, if the transistor in the power line were to fail short, the fan may run, even without commanded to do so,
the current could follow the path from A:1 - through the motor - via A:2 to the chassis point 31/2.
But I haven't been able to find the connector to the fan assemby yet, so it is possible that there is no easy way to keep power to the
fan while the command to run is disconnected.
Willy
water2xu
05-08-2011, 12:03 AM
2006 xc70 fan running none stop as soon as start engine due to AC high pressure sensor (or switch) problem

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my 2006 xc70 had the same problem, after scan it at shop and found AC high pressure sensor fault. After cleared the fault, fan stopped running continuously. waiting the order for AC high pressure sensor (or switch) to replace it and make the AC working.