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My wife's car (A4 B9 2016 estate) has started doing something funny recently after being parked up for a week.
When the driver's door is opened 15 seconds later the radiator fan comes on full blast and switches off 10 secs later. Engine is cold. Doesn't happen if passenger door is opened. Also,
If the ignition is switched on (and the engine is not started, and the A/C unit is turned off) then 15 seconds later the radiator fan comes on full blast and stays on indefinitely. After the ignition is turned off the fan will stop 45 seconds later.
My local mechanic has done a few tests and things it might be the radiator fan unit but doesnt want to go to the expense of changing that without being sure it will resolve the situation. He says he is getting a rad fan fault on his diagnostic system. I believe he isolated the thermostat as not being the issue.
Any suggestions on how to fully diagnose the issue before going to the expense of buying parts?
It's an Audi, step 1, full scan for DTCs. Then look at the measuring values for fan activation by the engine control module. If the fans are running hard, but the ECM is saying "yeah, I'm running them hard", that's a different approach to what might be wrong than "the fans are running? no it's not me" from the ECM.
https://www.ilcats.ru/audi/?function...=1&language=en
If you search on that page for radiator fan, there's far too many varieties to determine which given the no information about the vehicle. You need to look on your vehicle identification sticker and see what Dxx PR code and 8Zx PR code you have. You have a TDI, so you'll be 5C0 (5C1 is US safety standards).
If appears it's a pretty basic config for 2.0 TDI? Just 4 pins, power for the electronics, power for the motor, ground, and duty cycle command from the ECM.
Thank you very much for your time on this. I have tried to identify the radiator fan from the parts catalog but I am struggling.
I need someone with the expertise to look it up for me. (I got to this one but still not 100% sure 8W0959455J.)
I attach the VIN (which didn't seem to pick up the associated parts) and the 8Z5 and DN4 are probably the optional equipment codes of relevance.
Would you be able to identify the correct radiator fan part # for me, please?
If I were to get a radiator fan unit (from a scrap car), would that have a separate complete part # to identify the complete unit?
I am trying to get a full DTC scan done today ....
DEUA engine code
DN4 (2.0 TDI 110kW) + 8Z5 (not hot country)
no 0C_ (CO2 emissions) or 1D_ code (towing) or 5C_ code (safety standard) on the sticker; you'd need to get the full code dump for your VIN from erwin, partslink, dealership, etc, to confirm those.
Another vehicle PR code dump I have on hand that is French MY17 A4 2.0 TDI DEUA and also DN4 and 8Z5 is 0C7 and 5C0 and 1D8 (trailer hitch prep).
Yeah, something is up with that ilcats page, it's not showing the DN4 stuff correctly, at least not for me. Looking at another reference, we see the fan with integrated controller for DN4+8Z5 as:
8W0959455, replaced later by 8W0959455J, now replaced by 8W0959455AC.
Basically the same as the D94/D95 stuff on that page.
So you'd probably want to check the harness plug for 12v from pin 1 to pin 4 and 12v from pin 2 to pin 4. If 12v if missing on either of those, you have a blown fuse. Pin 1 comes from a big fuse at the jump start post block. Pin 2 comes from a little fuse in the front left of the passenger cabin. Pin 3 to pin 4 should be a voltage proportional to the commanded duty cycle by the ECM. For example, engine on but AC off, it's probably a low voltage. But turning on the AC should see the voltage jump up as the ECM wants the radiator fan blowing faster. If all that looks good, it's probably just a "replace the fan unit" task.
08-21-2023, 04:14 AM
Radiator Fan Audi A4 B9 (2016)
