[Jassen]

I’ve got an 06 E90 323i and I’ve been having trouble with my trans going into limp mode. I took some advice and decided to check the fluid and it was pretty dirty so I got some new fluid in there with a new filter today, it shifts great now but after driving it for 20 mins or so the problem popped up again. I had to have it towed last week because it got stuck in limp in the backroads, I reset the code and it went away so I could get it to the mechanics.

The fault code was 4F8D, I’m not sure what could be the problem, it only ever puts it in limp after driving it for a while, it’s been pretty hot here around 27-29 degrees Celsius, I was wondering if the heat had anything to do with it acting up as my trans feels good. Maybe I need a different oil for the temperature? I’d rather not shell out 3k for a new trans if it’s something I can fix for cheap ) I’ve seen a few posts about replacing the mechatronic sleeve or my solenoids, any help would be great )

[PhaceN52]

It should be the ZF 6hp, so the only right fluid is its ZF Lifeguard, did you follow the fill procedure with inpa/ista that asks to fill at 35°C and 40°C?

There's this service bullettin from bmw regarding your particular error:

"SI B 24 04 07
Automatic Transmission April 2007
Technical Service

SUBJECT
ZF 6HP19TU in Failsafe Mode with Fault 4F8D Stored


MODEL
E90, E91, E92 with N52K or N54 engines and the 6HP19TU automatic transmission produced from 9/01/06 up to 2/28/2007


SITUATION
The transmission goes into failsafe mode with fault code 4F8D (ratio monitoring, gearshift 5-4 – plausibility) stored in the EGS.

CAUSE
EGS software diagnostics is too sensitive.

This fault may occur during a 5-4 downshift only in vehicles with either low mileage, a replacement transmission, or after a reset of the adaptation values.

CORRECTION
On a customer complaint basis only, perform an adaptation run as described in the procedure below.

Note: The transmission adaptation occurs only at a transmission oil temperature of 75°C or higher.

Once a transmission oil temperature of 75°C is reached, carry out the adaptation run as follows:

In drive position "D", increase vehicle speed up to 4th gear (approximately 25 mph), but do not allow a shift into 5th gear.

Allow the vehicle to then coast to a stop and keep the vehicle stationary for approximately 15 seconds with the brake pedal applied.

Next, with the vehicle stationary, change from D to N and back to D again.

Repeat steps 1 to 3 approximately 10 times.

This problem is solved in series production beginning 3/01/07 with integration level E89x-07-03-510.

WARRANTY INFORMATION
Covered under the terms of the BMW New Vehicle Limited Warranty.

Defect Code
24 00 23 83 00


Labor Operation:
24 99 000


Labor Allowance:
4 FRU
WT
_________"




If this doesn't work I'd give a shot to new valvebody solenoids, as well as the 4 circular sleeves and the square one between said valvebody and the gearbox itself (and maybe a sonnax zip kit for your unit) before thinking about burned clutches or other internal damage... keep us updated!

[Jassen]

Hey, for the update I change the transmission fluid and did all the steps in the comment, it seems that the error only pops up when I’ve had the aircon on for a long period of time, otherwise I could drive for two hours and the fault wouldn’t pop up. It could be the heat as it’s really hot here at the moment or I’m guessing the transmission isn’t getting enoug volts once the aircon or other things have been turned on