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Mercedes-Benz Central Gateway Module ZGS (also referred to as CGW) may fail, causing various warning lights or systems to stop working.

Mercedes Central Gateway module is the hub that allows communication between various modules. Mercedes ZGW Gateway control module stores data for Mercedes ASSIST or ASSYST plus.

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Problems with this module can be challenging to diagnose especially if you are not specialized in Mercedes-Benz vehicles.

What is the Central Gateway module?

Mercedes Central Gateway module ZGS

Mercedes Central Gateway Module is the main hub that communicates with various ECUs and modules, including seat modules, front, and rear SAM, audio gateway modules, etc.

Depending on how and what component of the Mercedes Central Gateway module fails, you will notice various lights and disabled systems.


bad mercedes central gateway module cgw zgs warning lights

Symptoms of a bad Mercedes Central Gateway module usually vary from car to car.

No Communication

A common symptom of a bad Gateway Module is that there is no communication between an OBD-II scanner and one or more modules. Control modules that communicate via the Central Gateway module do not respond if the Gateway Module has failed.

The engine will start and run fine in some cases, but the vehicle may go in limp mode.

Intermittent Electrical Issues

The central gateway control module can also allow systems to work at times and then shut them down unpredicted times due to a bad or corroded connection or terminal. A bad CGW can also cause the engine to randomly shut off even when driving.

Random warning lights and messages

You will have several warning lights stay ON on your cluster, and several features stop working. Below is a list of warning lights and problems you may notice if your Mercedes Central Gateway Control module fails. This is a partial list, and symptoms can vary between various Mercedes models such as C, E, S, CL, CLK, CLS, ML, G, GL, R, SL Class.

One or more of the following lights may come on.

  • SRS/Airbag light ON
  • Check Engine Light ON
  • ABS or ETS light on
  • Battery Warning Light ON
  • Low oil light
  • Brake Light ON

Disabled Systems

When the Mercedes Central Gateway Module fails, one or more of these systems may stop working.

  • Radio / COMAND not working
  • Both front seats not working
  • Heated seats
  • Keyless Entry
  • Rear liftgate
  • Wipers
  • Turn signals
  • Lights
  • Instrument Cluster
  • Heated Seats
  • Sunroof

Common Problem


Mercedes Central Gateway Module may fail due to water damage.

It can also fail from internal software or hardware defects.

Damage to the Mercedes Central Gateway Control module can be caused by a blocked drain valve in the trunk floor.

mercedes blocked drain valve causing failure of central gateway module cgw



On some models, the Central Gateway Module is mounted on the vehicle's trunk floor, where water can easily damage the unit.

What to do?

If the Mercedes-Benz gateway module has failed and doesn't communicate with other ECUs, it will need to be replaced. Cleaning a Central Gateway Module terminal can be attempted, but it is rarely a success.

A new CGW module can be purchased at the dealer or online. You must get the CGW module coded properly with Star Diagnostic Scanner on eBay. The Star diagnostic scanner will need to have a subscription to complete online coding.

If you replace the bad CGW with a new one, you will have systems that will not work because they are not coded in the CGW module.

CGW/ZGW Gateway control module stores vehicle service history, VIN, and mileage of the car. You will need to code the original miles and VIN in the new ZGW module by cloning the information from your old Mercedes ZGW control module. If the ZGW data cannot be read, manual coding can be performed by the dealer or a Mercedes mechanic.

For example, the power seats may not work because they are not coded in the new CGW module. Keyless entry may not work because it needs to be coded in the CGW module. You need to code the CGW module and tell what modules and systems are installed on that vehicle.

CGW Part Numbers

Below you will find a partial list of Mercedes-Benz Central Gateway Control Module part numbers. This is for reference only, and you should never order parts based on this list. If you need to figure out the part number of your Mercedes-Benz, call a dealer and provide your vehicle's VIN.