View Full Version : Module question

02-26-2013, 12:36 PM
Hi, guys

If I'm not wrong, there are four modules in the module box in the 500:

- Base module
- E-Gas
- LH

Does anyone has information on what they exactly control and how?

I know these had been widely discussed here but I would like to get more information about how they work to get better understanding of the car brains. It may be a basic question, sorry, but I hope we, still dumb Mercedes owners, are still welcome ;-)


02-26-2013, 12:38 PM
More details are in the factory manuals, but in general:

- Base module - Power supply for other modules, plus trans kickdown, and AC compressor control
- ASR - Traction control and ABS
- E-Gas - Throttle body control and cruise control
- LH - Fuel management for the engine
- EZL - Ignition management for the engine

All of the above share data over the CAN.


02-26-2013, 12:43 PM

./me gives Dave a puppy eyes look: Maybe add some more to that? :)

02-26-2013, 12:48 PM
More details are in the factory manuals

Thanks so much for the quick reply but I was looking for something more. Anyway, I woudn't understand it because I haven't even been able to find it in the factory manuals. ;-)

Does the EZL receive any input from the LH module?

02-26-2013, 12:59 PM
Detailed info is buried in the factory manuals, including the CD-ROM, but you have to poke around quite a bit to find it.

The EZL receives data from and also sends data to the LH module. ALL the modules exchange information via CAN. That's the whole idea of CAN (Control Area Network).


02-26-2013, 01:08 PM

02-26-2013, 01:16 PM
There are actually 4 modules in the CAN box underhood, as indicated. A fifth module, the Diagnostic Module (DM) for US cars, is physically smaller, and is located in the passenger compartment, on the passenger side footwell.


02-26-2013, 01:18 PM
The DM is only present on USA and, I think, Canadian cars. Euro cars do not have the DM and also do not have the CEL (Check Engine Light).


02-26-2013, 04:05 PM
Thanks guys! I just found the info in the manual.

02-28-2013, 08:18 AM
One more question, if you don't mind: the module box blower is supposed to work all the time or only when it reaches certain temperature?

02-28-2013, 08:42 AM
One more question, if you don't mind: the module box blower is supposed to work all the time or only when it reaches certain temperature?
I believe it only activates at a certain temperature. It is controlled by the BM.


02-28-2013, 10:39 AM
The module box blower is switched on and off by a temperature sensor incorporated in the Base Module (BM).

The blower motor is switched on for 1.5 seconds after each engine start when engine speeds exceed 1,200 RPM, as well as when the temperature in the module box itself exceeds 60C.
The blower motor is switched off at a module box temperature of 55C or less. If the module box exceeds the specified temperature, despite the blower motor operating, then it stores a code 5 in the BM.


02-28-2013, 02:13 PM
Thank you so much!