R56 strange coolant temp sensor behaviour- fan stays on
Discussion
Hello mini owners. First time posting. I have searched a lot of UK and US forums but can't find this specific issue. I'm hoping you can help.
Fault: electric coolant fan comes on high speed mode for 5 - 10 minutes after shut down.
Finally traced to: the coolant temperature digital reading (using this trick: you tube.com/watch?v=KhFTyjIRaBU ) to the ECU is 'lost/overridden' whenever the climate control blower is turned on. This loss of coolant temperature information puts the car into failsafe mode, and switches the electric coolant fan on high speed mode. The same behavior can be simulated by simply unplugging the coolant temperature sensor.
This never happens unless the climate control is selected to on. Either simple warm blowing or proper aircon. Both options have the effect of 'losing' the coolant temperature signal to the ECU.
Does anyone remember seeing or hearing about this strange behavior?
What is worse is that once the signal is lost, it latches, but with no fault code. An OBD tool is needed to erase whatever is latched and return the coolant temperature signal. You can see this actually happening in the video. As soon as this is done the high speed fan stops.
This is a recent fault and the coolant temp sensor has been replaced with new, twice!
The car has only ever had one of the two infamous coolant fan speed relays and only one of the two fuses. These are not the issue.
Pictures and video explain more. Please help!
https://photos .app. goo.gl/dP5hGyCRXZYGT9Av5
Remove the two spaces in the link above to see video.
Bit more detail: the coolant temperature digital reading will display as designed all the way from ambient to 100C+ and back down again during a long drive. Providing no heating or aircon is selected on the climate control, the electric coolant fan will remain off after shut down.
If the climate control is turned on during any type of hard or soft drive, the digital coolant reading will be lost and replaced with three asterisks ***C (i.e there has been a loss of coolant temperature signal to ECU)
Fault: electric coolant fan comes on high speed mode for 5 - 10 minutes after shut down.
Finally traced to: the coolant temperature digital reading (using this trick: you tube.com/watch?v=KhFTyjIRaBU ) to the ECU is 'lost/overridden' whenever the climate control blower is turned on. This loss of coolant temperature information puts the car into failsafe mode, and switches the electric coolant fan on high speed mode. The same behavior can be simulated by simply unplugging the coolant temperature sensor.
This never happens unless the climate control is selected to on. Either simple warm blowing or proper aircon. Both options have the effect of 'losing' the coolant temperature signal to the ECU.
Does anyone remember seeing or hearing about this strange behavior?
What is worse is that once the signal is lost, it latches, but with no fault code. An OBD tool is needed to erase whatever is latched and return the coolant temperature signal. You can see this actually happening in the video. As soon as this is done the high speed fan stops.
This is a recent fault and the coolant temp sensor has been replaced with new, twice!
The car has only ever had one of the two infamous coolant fan speed relays and only one of the two fuses. These are not the issue.
Pictures and video explain more. Please help!
https://photos .app. goo.gl/dP5hGyCRXZYGT9Av5
Remove the two spaces in the link above to see video.
Bit more detail: the coolant temperature digital reading will display as designed all the way from ambient to 100C+ and back down again during a long drive. Providing no heating or aircon is selected on the climate control, the electric coolant fan will remain off after shut down.
If the climate control is turned on during any type of hard or soft drive, the digital coolant reading will be lost and replaced with three asterisks ***C (i.e there has been a loss of coolant temperature signal to ECU)
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