In our case Linde H40D, a Coding connector also came slightly loose. It's located in the armrest, where the hydraulic joysticks are connected.
I hope this will be useful.

Fault T 236
Precondition:
The controller detects that all inputs for the travel direction switch (N1:36, N1:37, N1:56, N1:72) are open.
Effect on the truck:
Stop
Possible causes:
Dual-pedal truck:
1. Coding connector (1X3) not installed.
2. Connections between coding connector (1X3) and controller (N1:36, N1:37, N1:56, N1:72) faulty.

Single-pedal truck:
1. Direction switch (1S2) not installed.
2. Connections between travel direction switch 1S2 and controller (N1:36, N1:37, N1:56, N1:72) faulty.