FN code on gears window! can't shift...

L

LAR2023

New member
Good afternoon everyone. Thanks in advance, any input is useful.
BMW E85 2004 SMG. Ran smooth as silk until recently. To make a long story short, I tried to start it yesterday. In the little window where the current gear is shown, a FN code appear. Couldn't switch gears or start it for a while. After a few tries (switch on, try to shift from first to neutral, switch off, take out key, repeat process) I was able to get it to N and start it. Let it run for a few minutes, took it for a spin, came back home.

Today, same thing happened. I am not moving the car, because I don't want to be stranded outside. I believe the culprit may have something to do with the shifting sensor.

So here are my questions:

1) Do you guys know what the "FN" code in the gear window stands for?

2) As you can tell, I am no tech expert. I don't want to take it to the dealer, becasue down here in Mexico, I might as well just scrap the car, dealerships are really expensive when diagnosing. What kind of scanner/process should I look for with and independent mechanic?

Any other thoughts are really appreciated!!!
 
Hi there. Can you hear the hydraulic pump pressurising when you unlock the car ? Does it pressurise frequently when the car is idling ? If so, it could be accumulator related/low pressure. Could also be clutch actuator or switching / selector angle sensor. You REALLY need to get the fault codes read to narrow things down.
Check if battery is good, minimum 12.5V. The SMG pump consumes a lot of energy and the ECU will not allow the motor to start if the pressure is not high enough.
If battery is ok and you don't hear the pump, check the SMG pump relay (Navy Blue)
If the relay is ok, check hydraulic fluid level in the reservoir on side of gearbox. If fluid level is good and no visible leaks then the pump is probably faulty.
If the pump is priming then you need to check the hydraulic pressure in INPA. Measure only with ignition on, no shifting. Hydraulic pressure should be around 45bar. If pressure is OK, visually check the clutch actuator to see if it is leaking. It's a VERY common issue of the 6-speed (Non-M) SMG.
Have a look at SMG Society website and send an email to them in Germany with codes and description of your problems. I have used their services/bought parts a few times and they are an excellent company to deal with. They sell many new and reconditioned SMG parts at sensible prices :thumbsup:
https://www.smgsociety.com/
 
Wow, thanks a lot for all the info! I can hear the pump working when I open the car. Haven't really noticed if it is working at idle. Currently working on getting a reliable mechanic to come to scan the car and try and solve this thing. Battery seems to be working fine. Will check on the hydraulic fluid.

Will also contact SMG society.

I owe you one at least a bottle of tequila, so let me know if you ever come down here!!!


Thanks
 
I have the scan code results for my car. it reads "Error code is 0027EC Digital Motor Electronics (DME) no message  (EG51) from EGS (Electronic Gearbox) control unit"
The original scan is in spanish, so I have translated it as best I can, and I am also attaching a picture of said message. 
I am actually in the process of moving from my current home. The little bimmer hasn't started in over two weeks, even though I crank it every morning, but the FN code still comes on the gear window. So I was ready to call a tow truck, and I thought "what the hell, let's try it one more time" and what do you know, it started. The yellow gear light was on, but I was able to drive it to my new home, a 3 mile-drive. It ran perfectly. As soon as I got to my new place, I turned it off, try to start it again, and the dreaded FN code comes again...

Would really appreciate any pointers.

Merry Xmas!
 
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