Fan on constantly from start up - help - CODES ADDED

synthedup · Post by **synthedup** » Tue Feb 13, 2018 12:13 pm

Would love some help on this.

Where is super Mike and other in the know?

Ducklakeview · Post by **Ducklakeview** » Tue Feb 13, 2018 12:20 pm

Remove the plastic cover at the front with the BMW logo on it. Underneath you'll see the power connector for the fan, it has two thick wires and a VERY fine green one. This is the speed sense signal from the fan back to the ECU. I have had a couple of cars where this has rotted away just near the connector, meaning the ECU doesn't get confirmation of the fan speed. This could be causing it to run the fan at max as a failsafe. I've had to dig into the connector and extend the green wire a little before soldering it back to the terminal.

Worth a look?

Mike

synthedup · Post by **synthedup** » Tue Feb 13, 2018 12:42 pm

Ducklakeview wrote: ↑Tue Feb 13, 2018 12:20 pmRemove the plastic cover at the front with the BMW logo on it. Underneath you'll see the power connector for the fan, it has two thick wires and a VERY fine green one. This is the speed sense signal from the fan back to the ECU. I have had a couple of cars where this has rotted away just near the connector, meaning the ECU doesn't get confirmation of the fan speed. This could be causing it to run the fan at max as a failsafe. I've had to dig into the connector and extend the green wire a little before soldering it back to the terminal.

Worth a look?

Mike

Thanks Mike,

Really appreciate that. I will take a look this evening

synthedup · Post by **synthedup** » Wed Feb 14, 2018 7:34 am

Ducklakeview wrote: ↑Tue Feb 13, 2018 12:20 pmRemove the plastic cover at the front with the BMW logo on it. Underneath you'll see the power connector for the fan, it has two thick wires and a VERY fine green one. This is the speed sense signal from the fan back to the ECU. I have had a couple of cars where this has rotted away just near the connector, meaning the ECU doesn't get confirmation of the fan speed. This could be causing it to run the fan at max as a failsafe. I've had to dig into the connector and extend the green wire a little before soldering it back to the terminal.

Worth a look?

Mike

Had a good look yesterday and all wires and connections look really good. No lose wires etc

Ducklakeview · Post by **Ducklakeview** » Wed Feb 14, 2018 11:16 am

synthedup wrote: ↑Wed Feb 14, 2018 7:34 am

Had a good look yesterday and all wires and connections look really good. No lose wires etc

Hmm.. Can you get access to the diagnostic kit, I'd be trying the actuations, to make sure the ECU has "full" control of the fan, and going from there.

Mike

synthedup · Post by **synthedup** » Wed Feb 14, 2018 12:45 pm

Ducklakeview wrote: ↑Wed Feb 14, 2018 11:16 am
synthedup wrote: ↑Wed Feb 14, 2018 7:34 am

Had a good look yesterday and all wires and connections look really good. No lose wires etc
Hmm.. Can you get access to the diagnostic kit, I'd be trying the actuations, to make sure the ECU has "full" control of the fan, and going from there.

Mike

Cheer Mike, I will take a look.

I spoke to a BMW specialist this morning and once i told them my issue they don't want anything to do with trying to fix it.

They have said it could be so many things they wont even take on the job.

They recommended changing the oil pressure sensor and coolant sensor.

Does anyone know were the oil pressure sensor is on a 2.0 N46 engine?

Ducklakeview · Post by **Ducklakeview** » Wed Feb 14, 2018 1:00 pm

Oil pressure sensor??

Firstly, why would that trigger the fan? IF it was a temp sensor, then possibly...

Secondly, if it's faulty, you would be getting a warning..

As I said, could be a multitude of things, hence the response from indy..

You need someone with good diagnostic procedures, and the correct equipment, rather than blindly replacing components, which will quickly become a lot more expensive than an hour or two spent on proper diagnosis.

Mike

synthedup · Post by **synthedup** » Wed Feb 14, 2018 1:27 pm

Ducklakeview wrote: ↑Wed Feb 14, 2018 1:00 pm Oil pressure sensor??

Firstly, why would that trigger the fan? IF it was a temp sensor, then possibly...

Secondly, if it's faulty, you would be getting a warning..

As I said, could be a multitude of things, hence the response from indy..

You need someone with good diagnostic procedures, and the correct equipment, rather than blindly replacing components, which will quickly become a lot more expensive than an hour or two spent on proper diagnosis.

Mike

Booked it into BMW Sheffield for next Thursday. £90 inc VAT for a guaranteed diagnostic.

They will also do a health check and wash/vacuum the car.

May take an M4 out whilst I wait hehe

Ducklakeview · Post by **Ducklakeview** » Wed Feb 14, 2018 1:35 pm

synthedup wrote: ↑Wed Feb 14, 2018 1:27 pm

Booked it into BMW Sheffield for next Thursday. £90 inc VAT for a guaranteed diagnostic.

They will also do a health check and wash/vacuum the car.

May take an M4 out whilst I wait hehe

Guaranteed diagnostic?? New one on me

Good luck..

Mike

ph001 · Post by **ph001** » Wed Feb 14, 2018 1:51 pm

A main dealer would be the last place I would be taking it!

Ducklakeview · Post by **Ducklakeview** » Wed Feb 14, 2018 1:53 pm

ph001 wrote: ↑Wed Feb 14, 2018 1:51 pmA main dealer would be the last place I would be taking it!

+1 on that I'm afraid. I suspect the "actual" bill will be somewhat more than £90..

Mike

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