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Ford S Max 2.0 2006 - Cooling fan fault, code P0691 fan1 control circuit low - Fixed #

Posted by Peter Holland on April 28, 2011, 5:21 pm

Year of Manufacture *: 2006
Engine Size and Code *: 2.0
( Optional ) Scanner Used: Dec Multiscan
( Optional) Fault Codes: P0691

I've got this car in with a fault with the air con system but it turns out that the air con won't work as the cooling fan does not operate. It logs code P0691 - Fan1 control circuit low.

The speed controller for the fan motor has 12 volts on it when connected to the speed controller but appears to be open circuit when I disconnect it. This doesn't seem to match the fault code as I'd assume that "circuit low" would mean that the ECU is not seeing any voltage from the speed controller.

I've got little information on this vehicle but I'm guessing its the same as a later Mondeo 2.0 TDCi. Can anyone tell me whether its possible to test the speed controller or can confirm if I should see a voltage from the ECU on the speed controller signal wire when its disconnected from the controller? I've tested the fan and confirmed that it is working ok. I'm guessing that I may have a broken wire or possible ECU fault but just need a bit more info to confirm it!

Re: Ford S max - Cooling fan fault

Posted by Bryan Smith <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT5330' width='330' height='300' border=0 style='border:none;'> on April 28, 2011, 10:51 pm, in reply to "Ford S max - Cooling fan fault"

Hi Peter,
If I remember correctly I think that these are controlled by PWM. I have had one of these that had corrosion within the signal wire insulation near to the multi plug. I replaced the offending section of wire but a year later it happened again, this time at the point where it went into the controller, so the only answer that time was a complete new controller/fan motor assy which I think was about £160. Water must have got into the wire at some point and worked its way along. Try scoping before and after the plug and near to the controller, or a multi meter with duty cycle capability should do just as well.
HTH's
Bryan
PS. Have just re-read your post when a bit more awake. I'm sure the controller wire is PWM switched earth which would explain the lack current when disconnected, assuming you are pulling the multi plug apart. If I am correct and you have batt volts when all connected that would mean a lack of earth, either in the loom or from the PCM. The signal should vary from 0v (fan running full speed) to 12v (fan off) but as I have said it's best to scope it.

Re: Ford S max - Cooling fan fault

Posted by Peter Holland <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT5256' width='330' height='300' border=0 style='border:none;'> on May 3, 2011, 9:33 am, in reply to "Re: Ford S max - Cooling fan fault"
Peter Holland

Thanks for your reply Bryan and I think you're probably right in saying that is could be a broken wire somewhere as this would explain the fault code of "circuit Low". I've checked the wiring to the fan speed controller plug but now need to trace it back to the ECU. I've yet to locate where this is hidden. Autodata shows it as being behind the drivers inner wheel arch somewhere. Time to start stripping the car down!

Fixed #

Posted by Peter Holland on May 4, 2011, 12:48 pm, in reply to "Ford S Max 2.0 2006 - Cooling fan fault, code P0691 fan1 control circuit low #"
Message modified by board administrator May 4, 2011, 3:45 pm

Found that the signal wire was broken in the loom where the fan loom joins the main engine loom. Had to clear the fault code before it would allow the air con to work but is all fine now.

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