Introduction

Introduction

Similar to control modules, Instrument clusters are also coded. This provides flexibility for changes in one vehicle to the next. Instrument clusters that are driven by control modules such as the:
- IKE in the E38,
- EKM in the E31
and the Instrument cluster of the E36 (excluding E36/5 and E36/7) are coded with the ZCS (Refer to the ZCS section [Tab 2]).

All other BMW instrument clusters utilize a coding plug to assign the specific market data to the instrument cluster.







Instrument cluster coding plugs have been used on BMW instrument clusters for quite some time. The early coding plugs where mechanically keyed coding plugs that opened or bridged circuits in the instrument cluster. This simple circuit bridge was the earliest form of coding. These "mechanical" coding plugs where used on the E23, E24, E28 and E30 vehicles.







With the Introduction of the E32 in 1988, instrument cluster coding plug design changed. They became electronic components that contain NV-RAM (Non Volatile - Random Access Memory). The electronic memory retains the vehicle specific information such as:
- Vehicle Identification Number
- Accumulated Mileage
- Service Indicator Information.
- Coding plug number
- Fuel Tank Size data
- Etc, Etc.

The change in the coding plug design provided data retention (accumulated mileage) which allows instrument cluster replacement with out loss of mileage (if coding plug isn't damaged).

There are several versions of instrument cluster coding plugs since the introduction of the E32. This section will provide an overview of the differences and provide identification and encoding information.