CANTCU isn't detected in the PC software
CANTCU needs +12V and GND to work properly.
Check that +12V and GND are present at the CANTCU connector (Pins A1 & A8)
Make sure your PC meets the minimum requirements -> Windows 10/11 operating system
CANTCU PC connection shows green but no information/serial numbers/connection
USB connection not correctly initialized or CANTCU not in normal operating mode.
Cycle power to CANTCU fully
Firmware update failed resulting in no PC USB connection
CANTCU stuck in bootloader mode.
Problem communicating with server
To protect against malicious intent, the amount of sessions is limited on a per-user basis. Using the flasher normally as intended, for flashing, you will NOT run into this problem. Spamming connections every 5 minutes trying to diagnose a "Transmission not detected" (see below) might block you out.
Try again one hour later.
Transmission not detected
This indicates that no transmission is found communicating correctly on CAN1 (transmission software information cannot be read). The reasons could be faulty wiring, unsupported transmission, or a 3rd party device/interface wired on CAN1 interfering with communication.
Check wiring
Verify that your transmission is supported
Make sure nothing else than CANTCU and transmission is wired on CAN1
Flash failed
As the PC program suggests, try again.
Make sure you don't have anything else than CANTCU and the transmission wired to CAN1. Anything connected to CAN1 OBD will interfere with flashing!
If flashing fails continously, contact support via email and attach logs from the failed flashes.
The cluster has outdated software but can be updated to show 8th gear properly.
Use BMW Tools (WinKFP) to update the cluster software
Shifts aren't smooth
If swapped from a manual car, DME/DDE might not have torque intervention requests active. Verify by looking at "Target Torque" and "Engine Torque" in CANTCU. While shifting, "Engine Torque" should follow "Target Torque" closely. If not, follow remedies below:
On most DMEs, a reset of variants is enough
On DDEs, a software flash normally is required
Transmission is slipping under load
Torque indication from DME/DDE might be inaccurate. This is common on tuned engines (cheated Nm2IQ/load/duration maps etc) due to poor tuning or limitations in the DME. Verify by looking at "Engine Torque" in CANTCU, and compare to real engine output.
If possible, correct the torque tables in the DME/DDE software.
Use "Torque Correction Factor" in CANTCU tuning to compensate
NOTE that the transmission also might just be mechanically worn out/broken. Increasing the indicated torque will not fix a mechanical issue.
All running values showing up normally in CANTCU (Engine RPM etc)
Brake pressed
Enough oil in the transmission
OEM shifter goes crazy when trying to put in S/M
This can happen when the shifter is physically wired to CAN1+2, but a CAN3 shifter is selected in CANTCU Configuration, causing two shifters to be present on the CAN-bus simultaneously.
Select correct shifter in configuration based on how your shifter is physically wired (OEM CAN1+2)