[Jenajs1]

Hi all,
I’m doing a CIC → NBT retrofit on my 2012 F10 535d xDrive (production 02/2012, and I’m completely stuck. Hoping someone here has seen this.

Car background (retrofits already done, working fine before NBT attempt):
• Full adaptive LED headlights retrofitted (lighting only — no high-beam assistant, no KaFAS2)
• ZGW replaced with newer ZGW-02 High Plus (with MOST connector) as part of the LED retrofit
• Cluster changed from 6WA to 6WB (digital)
• Everything worked perfectly in base configuration
• I-Step target: F010-24-11-520
NBT retrofit goal:
• Navigation on 6WB cluster
• HUD with nav
• Added parts: NBT unit, CID display, touch controller, antennas, microphones, cables

What I did:
1. Ran two new K-CAN2 wires from ZGW connector (pins 48 and 49) to NBT quadlock (pins 9 and 11)
2. Left the original K-CAN wires (orange-green and green) disconnected and insulated
3. In the trunk: disconnected Combox power, added optical bypass loop on the MOST connector
4. Left AMP untouched (original BE 9510 / PN 9264953 — HiFi Professional DSP, 677)
5. In E-Sys: edited FA — removed 6VC, kept 609, left the rest as it was (see FA screenshot). VO Model Year was already set to 07-13 from the LED retrofit.

The strange behavior:
NBT alone (MOST disconnected):
• NBT screen lights up (dimmer than usual, but on)
• E-Sys sees nothing — no NBT, no other MOST modules
NBT with MOST ring connected:
• NBT boots, shows time + vehicle data (fuel economy etc.)
• Within ~2 seconds, NBT screen goes black
• During those 2 seconds, E-Sys briefly sees NBT in “Read ECU”
• I managed to run Code on NBT during that window — it went through with 0 errors and my VIN is now written to NBT
• However, Read Coding Data fails — E-Sys throws a target/Ethernet connection error saying it can’t reach the ECU over Ethernet
• If I try Edit FDL it fails with a runtime error (NullPointerException in SvtCompareController.editFdl) — most likely because Read Coding Data didn’t complete in the first place
Bypass trick on ZGW optical connector:
• Put a loop in place of ZGW’s MOST connector (ZGW out of ring)
• NBT stays lit with MOST ring connected, even responds to steering wheel buttons
• But still no modules visible in E-Sys without ZGW in ring

Rollback test — CIC back in:
• Reinstall CIC → everything works perfectly
• Even with the modified FA (with 6NS instead of 6VC), CIC + all MOST modules show up in E-Sys correctly
• So the optical ring itself is physically fine
Key diagnostic info:
• NBT CAFD: 00000DED_003_015_033 (coded successfully, 0 errors)
• ZGW BTLD: 00000929_003_004_080 (last flashed ~2021, HWEL 000010F4_000_194_001)
• AMP: Harman/Becker BE 9510, BMW PN 9264953 (HiFi Professional DSP / 677)
• Current FA SA codes: 609, 610, 616, 644, 677, 698, 6AB, 6AK, 6FL, 6NS, 6WB

What I’ve tried:
• Multiple FA variations (with/without 6AB, with/without 616)
• Combox fully removed (power + MOST bypass loop)
• ZGW bypass (NBT stays awake but unreachable)
• Re-coding NBT with updated FA (succeeded once during the 2-second window)
Where I’m stuck:
I can’t get NBT to stay awake long enough to do a proper FDL edit, and the MOST ring collapses as soon as NBT is inserted. I only have PSdZData 4.40 Lite available for flashing, so re-flashing ZGW isn’t an option right now.

Has anyone seen this combination before? Any help appreciated — I’ve been on this for two days and I’m running out of ideas. Thanks!

[addy27]

You've not made any mention of using a CAN2 Vin Bypass adapter. Did you have the NBT coded to your VIN? Your wiring seems correct, with maybe an exception of one extra line that you need to REMOVE from the QuadLock (I'll have to dig up which pin/line it is), but you either need the NTB coded to your car, or use a can bus adapter that filters the VIN.

like this one : https://www.aliexpress.us/item/22518...2usa4itemAdapt

[Jenajs1]

Thanks for the quick reply!
Yes, NBT is coded to my car’s VIN successfully — I managed to run the VO coding during that brief 2-second window when NBT was communicating, and readCPS confirmed my correct VIN is now written to the NBT.

When E-Sys sees the unit for that brief moment, I run Read Coding Data on it and it completes with 0 errors. After that, my VIN appears in brackets next to the unit in the SVT tree — not the VIN from the previous car that was showing there before I managed to run Code with my car’s FA.
So no VIN bypass adapter needed in my case?
Currently I have:
• K-CAN2 added on pins 9 and 11 (from ZGW pins 48/49)
Let me know what else might need to come out😇