Hi,

I'm not sure if this is the right place to ask,l but here goes, I have a 2000 Ford Fiesta MK5, pride and joy has never let me down, and i have maintained it myself, as long as Ive had it, i found there was a problem with the Cooling fan not coming on and automatically, i changed the coolant temp sensor, as most places online, and on various other sources suggest. This has not cured the issue, and the fan does still not cut in.

Any other ideas?? i have checked the fuses, and checked the feed to the fan, and the issue seems to be no signal from PCM to start the fan. is this a common issue, if so how is this fixed.....

Thanks

AAE_Tech

have you checked the relay is functioning?

what happens if you disconnect the temp sensor with the engine running? does the fan cut in?

Ive just brought up the dash DTC's and have got p0115 which is the Engine Coolant Temp Circuit Malfunction.... I checked relays, and the resistance of the coolant temp sensor to ensure is not a faulty sensor, but havn't tried unplugging to see if the fan comes on....

UPDATE::

Ive unplugged the sensor, and yes the fan kicks in....

Are there no other ideas on this??

Thanks

unplugging the sensor puts it into limp mode, which brings the cooling fan on to ensure nothing does actually overheat.

I would say you need a new temp sensor..

Do you have Air Conditioning ?

Stef123, its had a new temp sensor, the temp sensor is giving all the correct readings through the OBD i have OBD equipment to read all the sensor readings....

Dan62, no it doesnt have aircon

Ok, so can we go back to basics here, you said your fan is not coming on so is your temp gauge reading above normal or are you loosing cooling fluid or some other symptom ?

You have changed the sensor and having it disconnected it proved the electrical cooling circuit and the ECU, not having aircon means there is no additional circuitry (relay and resistor).

Might be a long shot but suppose it could be the air intake sensor, can you see this on the OBD.

if not the sensor i was thinking about possible wiring damage but then you say the sensor appears to be reading correctly on the OBD?

is the engine running ok?

If you disconnect the sensor, can you see this on the live data using OBD?

On second thoughts, you say you found that the fan would not cut in? did it cut in before? on my focus i could not get the cooling fan to kick in for the whole time i had it but after a lot of digging it turns out that it shouldnt kick in until something like 120 degrees...and the engine never got as hot as that even holding a fast idle

STEF123: yeah, using an infra red thermometer and reading the sensor temp from the live data, within 1-2 degree, so therefore within tolerance, i remember the fan cutting in before when i've had the bonnet open when it had a small coolant leak in the past from the top hose, and the jubilee was replaced, it was vac filled, then ran up until the fan cut in..... I've had the engine up to 105 degrees, and despite my faith in the old 1.3 endura, i dare not take it any further!!

If you disconnect the sensor while reading live data you receive a fault message and you loose all live data. As far as asking is the engine running ok, the revs stick occasionally but i put that down the the idle valve needing a clean, and the tappets require adjusting on the next service, but other than that the old girls been getting abit thirsty since the fan hasnt been cutting in making me think, the PCM is running the car as if cold, therefore using more fuel and running rich.... But im not sure how advanced the PCM is on these, as i usually work on landrover diagnostics

Hi,

I have very similar symtoms with a 1997 Escort, with 1.3 Endura.

Temp sensor replaced, OBD data looks fine, but fan doesn't cut in.

Any success with tracking down this problem?

Misi