[play2own]

Since the end o July till now i have had a few days where my car would show the 1st orange overheating warning whenever im stuck in a traffic jam (about 5 times in 2 months)

I read the codes with ISTA 1st time it happened and it all indicated that i need to replace my radiator cooling fan but i wanted to get it diagnosed "properly" so i took it to a BMW dealer and they agreed that it was probably a dead fan

1A2004: Electric fan, control line: line interruption
1A2002: Electric fan, control line: short circuit to ground

So i ordered a 850w fan(part 17427640513) from Rockauto since i have a Msport and replaced it myself,also replaced the relay later because the fan only runs for 5 seconds stops for about 10s then runs for 5s again and keeps doing this till i get a error on the head unit saying that there is a problem with the fan and to drive moderately and completely stops working till i restart the car and does the same thing again

but a strange thing happens when im over 60kmh in sport mode and floor it i can get the temp to drop form 106c to low 80c in a mater of seconds
or if the car is stuck in traffic and over the 105c threshold and i restart the car instantly the fan will run properly till the car goes bellow 105c without pulling over

I did some research and apparently a failing water pump or thermostat can cause similar issues so i got both replaced yesterday and also did the coolant hose flange and the engine coolant temperature sensor since i have to drain the system anyways

and the issue still remains the same fan runs for 5s stops for a few runs again 5s etc till i throws a code even when the engine is off just with the ignition on with or without ac on (it seems to run full speed and pulls about 30A)

the code it throws after all items were replaced

-1A2804 electric fan, for operation: Limited
-1A2904 electric fan, for operation: Not Given

also get these 2 sometimes

421722: DME/DDE interface: Forced upshift due to thermal engine protection request
801224: Air conditioning compressor: Shut-down due to excess pressure in refrigerant circuit

my car currently has bm3 stg2 with fbo(cts high flow cat,ftp boost and charge pipe and vrsf 6.5 intercooler)

so now im thinking it might be a ecu issue or maybe just the pwm wire that goes from the fan to the ecu
the ecu is on a istep from 11/2018

any idea how to test the pwm wire or how to remove it from the ecu side in case i need to replace it?
the fan connector is ez to depin

any help would be greatly appreciated

[Blahx9]

You would need an oscilloscope to view pwm signal.
“ General notes

The electronic evaluation unit runs an internal fault diagnosis for critical states. If a fault is detected, operation is maintained as far as possible.

If activation by pulse width modulation fails, the electric fan is activated in the emergency mode with a fixed pulse duty factor.”


Have you tried reverting to stock tune? Did you adjust the cooling settings in the bm3 tune?
Since your fan is not failing to emergency mode, it seems like it’s wiring or ecu related.

[thejeremyman9]

Originally Posted by Blahx9

Have you tried reverting to stock tune? Did you adjust the cooling settings in the bm3 tune?
Since your fan is not failing to emergency mode, it seems like it’s wiring or ecu related.

+1 for these tests. I would completely uninstall BM3 and see if the issue still occurs. If it does, you can at least rule out a software issue.

You can then try the cooling settings as these will change the coolant temp target and make the thermostat open sooner (lower temp) and run the fan correspondingly more. The situation you described where the coolant temp quickly drops when you drive aggressively in sport mode is intended and is in the OEM tune. The coolant temp varies depending on ambient temp, driving mode, and driving conditions. Higher ambient temp, sport mode, and more aggressive driving all lower coolant temp target.

Also, i assume you did the coolant bleed procedure?

[play2own]

I did try the stock tune and it was the same
I never tried max cooling but i can give that a try
also did the bleed procedure a few times

today im going to replace my coolant temp sensor again because the new one i got failed in 1 week and is now showing -128 on the hidden menu

Im going to go over some a the wiring by the front + battery terminal maybe something is lose and causing wired electrical problems but im starting to think my ecu does have a problem

[BashShah]

I think you should go back to Dealer.
Here is why.
and you need to specifically as for this, and it should be 1 hour Labour cost only for this.

So you went to dealer and they simply scanned it and agreed with your findings.
so whether they scan or you scan is the same shit.

What you want to do is, book the appointment and ask to speak to the shop foreman before turning your car in.

Tell the shop foreman the truth and tell him all you have done so far.
Also tell him about the 5 sec on/off fan issue.

The shop foreman should connect your car to his shop computer a different way.
They have a IN-BETWEEN Harness between DME and Car plus various other parts.
This will tell you exactly what is failing where and why.

It should cost no more than 2 hours.
You will save a lot of time going this route.
Don't just replace parts.

Good luck and keep us posted.
btw, first n55 over heating issue I read.....interesting.

[play2own]

This is what i wanted the to do the 1st time i went in

Im probably going to try a different local bmw dealer this time and request exactly what you mentioned if i don't find anything today

[play2own]

So i went to BMW today and they insisted that my car should use the 600W fan even tho the original fan from factory was the 850w variant

they say that only 2 fans are compatible with these cars 400W and 600W

here are the pictures of my dead fan with 850W that came from factory and ran great till it stopped working properly

View post on imgur.com

View post on imgur.com

im so mad from arguing with these service managers and telling them that the car came form factory with this fan and them telling me it impossible

[Wgosma]

....find a good independent Euro/German shop.

[play2own]

the dealer also said that the wire that goes from the fan to the DME worked good and that if its not the fan the next thing to change would be the DME

[play2own]

Replaced the fan with a original BMW 17427640513(slightly newer revision that was on the car) from fcpeuro and everything seems to be working fine

lesson learned don't buy non original parts even if they have the same exact part number 17427640513