S1 111S - Fan Question

[pjlarge]

Hi All,

S1 111S - the fan seems to be acting up. The dash temp is reading normally but once the fan comes on it'll not switch itself off again, it just keeps running.
Additionally, if I run the car so the temp comes up to 86* or thereabouts, then shut it off for a few minutes then start it again, the fan will run continuously despite it not being at the trigger temperature to actuate the fan.

Does this sound like a bad sensor, sticky relay, bad earth or a combination?
...and if it's the sensor, which sensor is it and where is it located?

Many thanks

Phil.

[Corranga]

I believe the ECU (and fan) and the Stack (dash) are fed from different sensors, so don't presume that the dash reading correctly isn't a sensor issue.

I'm not educated enough to say this is 100% your issue, I just recently decided to replace the sensor due to having the coolant system emptied at the moment for a bit of a rebuild.

Both are standard Rover MG parts, I bought both from eBay for about £20 total.
The ECU sensor is brown and has Rover part number: MEK100060
The stack sensor is blue as Rover part number: YCB100420

I guess you could read the resistance across the sensor to see if it's functioning properly..

[mwmackenzie]

There are 2 temp sensors one for the dash and one for the fan, I believe they are prone to feking up at some point, just read the above which is indeed spot on...

[robin]

The ECU will switch the fan on whenever it thinks that the reading it is getting from the sensor is incorrect ... it's a safety measure to prevent it overheating when the sensor fails in a way that reports "cold" all the time, regardless of actual coolant temperature. The stack sensor sounds like it is OK. The ECU sensor could well be bust (not uncommon) or you have a wiring fault (broken wire at sensor, corroded plug, ...).

Cheers,
Robin

[pjlarge]

Good info thanks. Despite having every tool known to man I don't have a meter so I'll just order a new ECU sensor to start off.

Does the ECU coolant temp sensor affect VVC actuation as well? (suspect this'll be a yes) - the car feels pretty slow, but I'm not sure if that's because I got used to Honda power and now the Porsche...

[robin]

Probably ... I don't have any documentation on that level of detail of the ECU.

Cheers,
Robin

[pjlarge]

Brown sensor seems to have fixed it, thanks for the advice all.