Why Are Later Model ECMs Programmed, Not Variant Encoded?

Why Are Later Model Engine Control Modules Programmed, Not Variant Encoded?







Earlier BMW engine control modules (M1.x Systems) were variant encoded (see TAB 3). As the control systems progressed, variant encodable control modules became obsolete.

Control module encoding (ZCS) is and will continue to be the preferred method for supplying all variations of certain control systems ie: ZKE, IHKA, ASC, etc.

Unfortunately, encodable control modules are only as up to date as the software loaded in them.

As the pace of system upgrading and updating increased year after year, the software in the control modules also had to be updated. BMW implemented programming as the method of updating

control module software without replacing the entire control module. Programming control modules also offers additional cost savings and adds additional flexibility in the parts handling and distribution processes.

All engine control modules since the M3.1 system are only programmable. Engine control modules are suitable for programming due to the possibility of rapid control system updating.

Example:, a service action requires a change in a particular engine control function. To achieve this, the software program in the engine control module must be modified to change the required parameters.

Solution A: Replace vehicle control module with a control module containing updated software.

Solution B: Update software in existing control module.

Of course solution B is the quicker and more cost effective method.