[OneOneSix]

Hi All.

I have a 2018 LCI2 M140i with the latching stalks and I'm trying to change the SZL to one where the stalks always return to centre. I also wanted to have a future upgrade path to a heated steering wheel so after doing some research, I bought SZL p/n:6827370 with clock spring p/n:6992509.

Physically changing the SZL was very straightforward (thanks to the fabulous guidance here). Upon powering up the car, the steering wheel buttons worked fine but neither stalk would work, and the wipers ran constantly. I tried coding to the advised non-rastend settings but that had no effect. After scanning with ISTA, it gave me the following fault list:

030350 K-LIN 16 steering column switch cluster (SZL): Missing LIN slave (Existent = no)
030352 K-LIN 16 Message (ST_SZL_LIN): Alive counter fault (Existent = yes)
D35448 SZL interface (operation, wiper switch, ID: 0x2A6) Signal invalid (Existent = yes)
D90C0A LIN master K_LIN_16: No communication (Existent = yes)
D90C0B LIN master K_LIN_16: Communication faulty (Existent = yes)
D90C0E LIN master K_LIN_11: Communication faulty (Existent = yes)
E12C35 Signal (steering column switch operation 0x1EE) invalid. Transmitter SZL/FEM/BD... (Existent = yes)

After admitting defeat for the day, I reinstated the old SZL+coding and cleared the fault memories - all was well again with no faults.


I've narrowed the problem down to three possibilities:

1) The new (used) SZL is faulty,
2) SZL p/n 6827370 is not compatible with my car,
3) I've done something wrong!

I would be most grateful if anyone could help me work out what is going so badly wrong!

Thanks in advance.

[anom3]

I won't be of much help but:

I have done this retrofit on my 2012.12 prod 335.

i purchased a used szl for an f10 and it was pretty much plug and play. zero coding involved zero error codes after the swap.

for what it's worth the f10 szl is known to work just fine in the f30 except for the heated steering wheel switch which requires a diode + resistor soldered to make it work. there is a write up about it on drive2.ru.

if you have the option to return the szl and try a different part nr.

[OneOneSix]

After more digging around in RealOEM, I'm leaning towards a compatibility issue after seeing the label "nonexchangeable retrospectively" against 6827370. Perhaps I may have better luck with a 9368599 or 9330565...