M-codes are codes for options that could be orderded.
The M stands for Mehr oder Minder , translated More or Less options
The list below tells you what the M-code means and the link will show you the parts that where involved in the package or option.

– 20 MPH Speedometer (export)
– 24 Sealed beam head lamps and red tail lights (USA & Canada)
– 36 Side flashing indicators for Italy
– 56 Steering/ignition lock
– 75 Mud flaps – front and rear
– 106 Heavy duty shock absorbers
– 119 Eberspacher BN4 gas heater
– 124 Yellow headlamp glasses
– 140 Fire engine as specified by German DIN specifications
– 142 Sliding door on both sides
– 151 Eberspacher BN4 gas heater
– 156 Larger oil bath air filter – 1500cc
– 161 Sliding door – Panelvan, 1-side
– 162 Sliding door on both sides – Panelvan
– 163 Sliding door – Microbus
– 164 Flashing front indicators, used from 06-04-1957
– 164 Sliding door – Deluxe
– 169 Sliding door – Kombi
– 172 Visible location of brake fluid reservoir (Benelux-Belgium, Holland and Luxembourg)
– 175 Overriders all models (Except types 26 & 265)
– 176 Same as M175 ( Pick-up and Double Cab, Export)
– 194 Heavy duty mirror arms
– 196 Asymmetric headlamps for RHD
– 200 Single cab with enlarged steel bed, Payload 940Kg
– 201 Single cab with enlarged steel bed, Payload 910Kg
– 203 Eberspacher BN4 gas heater
– 215 1 ton payload and 1500cc engine (until October, 1964)
– 216 1500cc engine (until October, 1964)
– 510 Upper divider between cab and cargo area
– 520 Sliding doors left and right
– 616 Back-up lights
– 620 12v system (standard from August, 1966)