Hello everyone, I’m having a VERY odd problem with this car of mine. The fans are not working as they are supposed to.
Fault Code: ECM-P048087 Fan 1 Control Circuit Bus Signal / Message Failures. No Signal
Here’s what works:
- car is cold, you turn on the A/C >> both fans kick on at about 15%
- if I pull the coolant temp sensor to provoke 100% panicmode: That works just fine. Both fans will kick on to 100%.
- Temps look realistic on OBD, so I guess the sensor is fine
Here’s what doesn’t work:
- when the engine reaches operating temp and the A/C is off, the fans stay off, no matter how hot the car gets.
- when the engine reaches operating temp and the A/C is on the fans stay at 15% as if the car doesn’t care about coolant temperature.
- if you turn off the car, the fans stay off, no matter if A/C was on or not and no matter how hot the coolant is at that moment. As far as I understand the fans should keep spinning for some time if the car is hot enough. Mine don’t.
Needless to say the car overheats when it’s not freezing outside and you don’t drive it like a granny. Since it’s a diesel, which usually keeps pretty cool, it doesn’t overheat spectacularly, but it does overheat.
Overheating plays out as follows:
Car overheats when it briefly reaches operating temp at 85°C. Temps will rise to 105°C then rapidly go down to 90°C. Low Coolant Warning will come on. Coolant is boiling. If you turn of the car and wait a minute the coolant will rise to where it needs to be again.
Here’s what I already changed:
- – thermostat housing (came with a new sensor too)
- – two full coolant flushes. Now with official volvo coolant
- -4 new cooling fan modules
- first was the original one that came with the car
- second and third was cheap 35 bucks ones new from ebay
- fourth one was a 100 bucks one from the most reputable volvo parts shop in europe (skandix)
- second and third was cheap 35 bucks ones new from ebay
- first was the original one that came with the car
I have not checked the big 60/80 AMP midi fuse for the fans yet, because frankly I don’t understand why that would be broken since the fans CAN AND WILL kick on up to 100% if panic mode is happening. How would that work without a fine fuse.
Appears as if signals are sent, but not worked with. After all the signal for “A/C is on, blow at it a little” and “omg idk how hot it is, full throttle!” work.
Please help 
(Vida and a dice tester are available to me, same as d5t5 diag license. Been working on cars for like 12 years, so feel free bombard me with the professional lingo)