Mk3 focus 1.0 ecoboost problem with fan

[Birminghamfloyd]

Hi all i have a 2015 focus 1.0 ecoboost 2015 plate never had 1 fault untill yesterday i had a mot on the car on friday picked it up it was fine drove it following day it was fine but yesterday start the car engine light is on with fault code p0098 also the fan is constantly on not the big fan the small aircon 1 standing in front of the car its the fan on the left ? So i believe p0098 it is Intake air temperature sensor 2 circuit high voltage so ive change the sensor the one next in the air box well on the air pipe that goes into airbox had the fault removed and it came straight back on fan is still constant ive pulled the relays out fuses out fan still permanent on (with fuses and relays out )ive looked online everywhere people saying make sure its not set on aircon on panel its not ive checked engine light still present and so is the constant fan

temperature gauge gets to about half way with around 20mins of driving no coolant loss no bubbling heaters working on hot and cold please anybody have a idea what it could be atall???

Read more: https://www.autocodes.com/p0098_ford.html

[JW1982]

This is not the aircon fan. The aircon uses the normal (large) fan. The small fan is for the intercooler. This fan is only activated in extreme situations when the intake air temperature is pretty high (for example at very high ambient temperatures). 

DTC code P0098 means that the intake air temperature circuitry developed a high circuit (not a high voltage). This basically means that there is an open connection somewhere in the circuit. This can either be caused by a defective sensor or a wiring defect. Since changing the sensor did not solve the problem there will most likely be a wiring problem. 

[Birminghamfloyd]

Hi thankyou so when looking at the fan in question i only see a black and red wire going into the fan coming out of the fan its goes into a grey connector block when i unplug this the fan goes of where do i start to look please?

[JW1982]

You should start investigating the sensor wiring. The intercooler fan wiring has nothing to do with it. The fan is controlled by the PCM based on the intake air temperature. In case there is something wrong with the intake air temperature circuit the PCM runs the intercooler fan at maximum speed because it can not determine the actual intake air temperature. 

I suspect that the problem is caused by a wiring defect but in worst case scenario the problem can also be caused by a defect inside the PCM. The actual cause of the problem can only be determined by proper diagnostics and excluding other possible causes step by step. Personally I would start measuring the wiring between the PCM and the particular sensor(s). 

[Birminghamfloyd]

Ok thankyou my fuel is going down alot quicker now and still cant find the fault😌

[Birminghamfloyd]

Welli its booked into ford today for software update (recall) they said whilst it there they will look at it for me. 🤞ive spent 2days looking at all connectors etc checking wires still the same 

[Elosta]

Hi, 

have you got this sorted? I have the same problem with my Ford Focus 2016 1.0! 

[KatJH]

On 8/31/2022 at 9:27 PM, Elosta said:

Hi, 

have you got this sorted? I have the same problem with my Ford Focus 2016 1.0! 

Hi did you find out what was wrong? I have the same problem with my 2015 Focus. At the garage at the moment but they can't seem to find the problem.