Subject: error code: engine cooling function control Author: dbm32 : member since September, 2007 : 18 posts Posted on: 2010-10-25 16:06:51

I have a 2000 540 iT touring wagon. Over the summer I have noticed that the aux fan has not been running regardless of the conditions. On hot days the AC would not blow cold air when I first started the car. Once I was moving and especially at highway speeds the AC got ice cold. After driving a while the mechanical engine cooling fan draws enough air to keep the AC running cold. The high and low side pressures looked normal. From all my research and observations there appears to be something not working with the aux fan or the fan controller. All my fuses are fine.

My Peake code reader gives me an error code of OF 8d: engine cooling function control. I have read several old posts on the same subject and was about to try Jim Cash's suggestion of shorting the over temperature sensor to try to get the aux fan to run when my water pump bearing failed and torn up my main drive belt. Obviously not a good idea to run the engine now. Since I will have to pull the front of the car apart to change the water pump and other parts, I was wondering if anyone knew of a way to test the fan at it's connector interface. I have the newer variable speed fan (without relays) so there is 12 V at the connector when the car is on. I have not been able to find out what the control pulse is suppose to be. I have read that it is pulse width modulated at 10 to 100 Hz, but I do not know the characteristics. My guess is that it is 3-5 Vdc. Any suggestions? Now would be the time to change the aux fan if it is bad. Just don't want to change it if it is good.

• error code: engine cooling function control - dbm32 2010-10-25 16:06:51 (312 views)
  • Re: error code: engine cooling function control-Update - dbm32 2011-03-31 22:08:01 (83 views)