Fan failure

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Anonymous

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Hi folks,

My car beeped and showed a yellow signal above the temperature gauge on Saturday. Ended up parking the car in Kingston to ensure I did no damage and getting a taxi the rest of the way. I'd been sat in traffic, aircon on and roof down, for about half an hour.

Got the car home later Saturday night when it was cooler, with the aircon off and heaters blowing warm air and the temp didn't ping. However, when I got home and scanned the car with Carly for BMW, it threw up a "Fan failure" error. I also noted I hadn't heard the fan on the entire journey...

The fan spins OK but is clearly not activating... any ideas? Is there anything I can do, checks or tests wise, or does it really need an expert to check it over?

Thanks as always,

James
 
Get it plugged in buddy and see what it says
Sometimes they don't talk to each other
The water pump and the fans are linked apparently
And to the ecu
 
According to WDS:
Electric fan, S54 engine

Under certain operating conditions, the engine control activates the electric fan at various speeds.

The electric fan is activated by means of a power output stage directly on the fan motor. The motor control unit activates this power output stage by means of a square-wave signal with duty factors (variable pulse width) between 10 and 90 %, thus controlling the various speeds of the electric fan. Pulse duty factors less than 5 % and greater than 95 % do not trigger activation but rather they are used for fault detection purposes. The power output stage features its own positive and ground supply.

The fan speed is influenced by the coolant temperature at the radiator outlet and the pressure in the air conditioning system. The fan speed is reduced as the vehicle speed increases.
Click to expand...

The fan has an inbuilt control module with connections for GND (pin 1), power (pin 2) and control signal (pin 4). One would expect that an issue with any of the sensors would flag a sensor-specific fault code, so it's more likely to be the fan itself. I wonder how the system determines a "fan error" without any actual feedback signal from the fan? Unless you have some way to generate the 10% and 90% PWM signals required to activate the fan it will be difficult to test out. I don't suppose you have INPA available?

Also of interest:
Coolant Temperature Sensor at Radiator Outlet

This temperature sensor is fitted in the outlet hose of the radiator and registers the coolant temperature after it flows out of the radiator.
The quantitative signal of the sensor is the most important factor for activation of the electric fan. The engine management system activates the electric fan.
Click to expand...
With that in mind, disconnecting the temperature sensor would probably cause the car to bring on the fan immediately as a form of protection, but the DME is also likely to freak out about it too.
 
When my water pump was in trouble & started to fail, I noticed the fan would trigger from a cold start straight away with cycling up/down operation.
Replaced electric pump & fan back to normal.
Rob
 
D4dawg said:
Get it plugged in buddy and see what it says
Sometimes they don't talk to each other
The water pump and the fans are linked apparently
And to the ecu
Click to expand...

I'm guessing I need more than Carly app for BMW? As that just comes up with the fan failure error.
 
Mangozac said:
According to WDS:
Electric fan, S54 engine

Under certain operating conditions, the engine control activates the electric fan at various speeds.

The electric fan is activated by means of a power output stage directly on the fan motor. The motor control unit activates this power output stage by means of a square-wave signal with duty factors (variable pulse width) between 10 and 90 %, thus controlling the various speeds of the electric fan. Pulse duty factors less than 5 % and greater than 95 % do not trigger activation but rather they are used for fault detection purposes. The power output stage features its own positive and ground supply.

The fan speed is influenced by the coolant temperature at the radiator outlet and the pressure in the air conditioning system. The fan speed is reduced as the vehicle speed increases.
Click to expand...

The fan has an inbuilt control module with connections for GND (pin 1), power (pin 2) and control signal (pin 4). One would expect that an issue with any of the sensors would flag a sensor-specific fault code, so it's more likely to be the fan itself. I wonder how the system determines a "fan error" without any actual feedback signal from the fan? Unless you have some way to generate the 10% and 90% PWM signals required to activate the fan it will be difficult to test out. I don't suppose you have INPA available?

Also of interest:
Coolant Temperature Sensor at Radiator Outlet

This temperature sensor is fitted in the outlet hose of the radiator and registers the coolant temperature after it flows out of the radiator.
The quantitative signal of the sensor is the most important factor for activation of the electric fan. The engine management system activates the electric fan.
Click to expand...
With that in mind, disconnecting the temperature sensor would probably cause the car to bring on the fan immediately as a form of protection, but the DME is also likely to freak out about it too.
Click to expand...

I don't have INPA unfortunately as my laptop screen is cracked.

I've succumbed to booking it in with Walkers Autotech again so they can have a gander.
 
Scooba_Steve said:
Fix the screen, usually less than £40 and plenty of disassembly videos online :)
Click to expand...

It's an old Vaio and doesn't like to start up some of the time, so not that fussed. Not sure how much I'd get out of INPA?
 
JAD said:
Scooba_Steve said:
Fix the screen, usually less than £40 and plenty of disassembly videos online :)
Click to expand...

It's an old Vaio and doesn't like to start up some of the time, so not that fussed. Not sure how much I'd get out of INPA?
Click to expand...
In INPA you should be able to instruct the DME to switch on the fan. Then you can do further diagnostics ;)
 
Fair enough, I have inpa working on my tablet so maybe you could use another machine?
INPA is often good for activating things and getting live values.
 
JAD said:
Scooba_Steve said:
Fix the screen, usually less than £40 and plenty of disassembly videos online :)
Click to expand...

It's an old Vaio and doesn't like to start up some of the time, so not that fussed. Not sure how much I'd get out of INPA?
Click to expand...

Common basic faults worth eliminating are corroded connector blocks and faulty relays, and can't INPA be used to initiate test procedures on most of the systems including fans and pumps etc to check they are working?
 
Thanks for the above - at this stage, I might as well spend the £40 of screen fixing for a laptop I'm unlikely to use on diagnosing it with Walkers. Thanks for the input folks!
 
Had this problem the weekend. Fan just wasn't cutting in when it was over heating. Changed the fan and all good. Any e46 3##ci fan fits straight into mine. I've modified the wiring loom so I can plug z4 fan or e46 (two different plugs)
 
dannytheduck1985 said:
Had this problem the weekend. Fan just wasn't cutting in when it was over heating. Changed the fan and all good. Any e46 3##ci fan fits straight into mine. I've modified the wiring loom so I can plug z4 fan or e46 (two different plugs)
Click to expand...

How much did that set you back, Danny? Not keen on modifying but more to the point I'm fairly certain the E46 guys use our fans as upgrades, as ours are more powerful @ 600W? Correct me if I'm wrong of course!
 
JAD said:
How much did that set you back, Danny? Not keen on modifying but more to the point I'm fairly certain the E46 guys use our fans as upgrades, as ours are more powerful @ 600W? Correct me if I'm wrong of course!
Click to expand...

I believe you are correct so I'd be hesitant too
 
Well good news on this one, folks - it turned out to be a loom issue. Popped the car into Walkers Autotech middle of last week and had the car home on Monday (due to my diary). They also painted the calipers and the thing looks superb! Very happy once again. Back goes the £550 fan to Harry Fairbairn, although once again, very quick delivery from those guys.
 
JAD said:
dannytheduck1985 said:
Had this problem the weekend. Fan just wasn't cutting in when it was over heating. Changed the fan and all good. Any e46 3##ci fan fits straight into mine. I've modified the wiring loom so I can plug z4 fan or e46 (two different plugs)
Click to expand...

How much did that set you back, Danny? Not keen on modifying but more to the point I'm fairly certain the E46 guys use our fans as upgrades, as ours are more powerful @ 600W? Correct me if I'm wrong of course!
Click to expand...

Cost me £5 for the plug and an hour of an auto electricians time. I'm Pretty sure they are all 600W fans on the big engine e46s. Has to be off a Ci though.
The fan I installed does the job very very well even when I give it some stick. Will be ripping the complete cooling system out come autumn and installing a huge rad and uprated fans.
If anyone needs a good auto spark in the uk, I can recommend a friend who is ex cosworth and ralliart. He is also mobile if needed.
 
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