We swapped the stock BCM of the Polo GT with an advanced model last weekend. It was relatively easier than I had thought and pretty much straightforward. As always, I have documented the procedure here. If you plan to retrofit cruise control in your car, you might have to replace the BCM. Read on to find out.
CECM - Central Electronics Control Module
BCM - Body Control Module
The terms CECM/BCM are used interchangeably and they essentially mean the same component. The BCM is an electronic control unit that monitors and controls several functions in the car such as the interior and exterior lighting, the central locking and anti-theft system, interfacing with the vehicle’s instrument cluster, HVAC system, rear-view mirrors, wipers etc. The BCM communicates with the car’s other control modules through the CAN bus.
The BCM gets its input from the several sensors and variable resistors mounted onboard the car. For instance, the rain sensor will sense the droplets on the windshield and will close the windows and the sunroof automatically, and will turn on the wipers if the BCM has been programmed to do so.
Or if it gets dark, the light sensor will sense the intensity of light falling on it and will turn on the headlamps automatically.
Another classic example is speed sensitive door locks - if the speed of the car exceeds 15 kmph, the doors auto-lock.
All these functions are controlled by the BCM.
There are BCMs which provide a basic set of functions (e.g. central locking, fog lights etc.) and those that have advanced features (e.g. cruise control, static cornering lights, OEM bi-xenon projector lights etc.)
From Ross Tech's website, for the Polo 6R this is how it is:
Basis+ Part Numbers: ***-937-084-***
Medium+ Part Numbers: ***-937-085-***
Supported Features (like Basis+ and additionally): Central Locking, Anti-Theft-System, Outside Mirror Heating, Seat Heating
Medium++ Part Numbers: ***-937-086-***
Supported Features (like Medium+ and additionally): Remote Control
High+ Part Numbers: ***-937-087-***
Supported Features (like Medium++ and additionally): Cruise Control System (CCS), Anti-Theft-System LIN-Databus (for Alarm Horn)
Reku (Recuperation) Part Numbers: ***-937-088-***
Supported Features (like High+ and additionally): Start/Stop System (with Recuperation)
Licht (Lighting) Part Numbers: ***-937-089-***
Supported Features (like High+ and additionally): Lighting Functions (LED DRL, Bi-Xenon etc.)
Licht/Reku (Lighting/Recuperation) ## Part Numbers: ***-937-090-***
Supported Features (like High+ and additionally): Lighting Functions (LED DRL, Bi-Xenon etc.), Start/Stop System (with Recuperation)
As suggested by Ross Tech, only BCMs ending in 087 and above supports cruise control.
BCMs with 434 MHz radio carrier frequency ends with the letters B, D, F, H, K, M, P, R, T. Pick up one of these if you are looking to upgrade.
These BCMs are used in India, EU, South Africa and Russia.
