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Sprinter and Metris Vans in a parking lot.

PSM / MPM (ED5) Information

Interface between your vehicle and your electronic systems.

PSM Description

Painting contractor working out of his upfit Mercedes-Benz Sprinter Van.

Mercedes-Benz offers Programmable Special Module (PSM), a fully multiplexed electronic system networked to the vehicle CAN bus system, to Sprinter and Metris. PSM is an optional electronic control module that is the only Mercedes-Benz approved analog and digital gateway into the vehicle’s electronic system. PSM provides an interface between the van and auxiliary electronic systems and creates a host of possibilities for vehicle upfit.

PSM is installed in the left seat base in both Sprinter and Metris, and the fuses for PSM are located in the fuse box on the left seat box frame.

PSM is developed specifically to provide customers, upfitters, and fleets a hardware and software access to individual types of CAN bus data for electrical installations and full functional integration of their products. The access to the CAN bus data via PSM allows the customers and upfitters to read specific vehicle information and use the information to control specific vehicle functions. Vehicle information from the CAN bus through PSM can be evaluated and routed onto the body manufacturer CAN bus or onto the PSM multifunction inputs and outputs when upfitting or installing aftermarket electronic equipment.

Electrical contractor working out of his upfit Mercedes-Benz Sprinter Van.

The PSM control unit hardware and software and the corresponding functions differ between the Sprinter and Metris models. Some of the described functions below may only be available on a specific vehicle model type.

Vehicles ordered with the factory option code ED5 come with PSM installed on the vehicle. PSM can also be retrofitted only onto vehicles equipped with PSM prep code, ED8. The side sliding door electric step, the factory option codes T57 or T58, comes with PSM module included.

For more information, please check PSM Bulletin and PSM section on Body Equipment Guideline on Upfitter Portal.

PSM Function

PSM serves as an interface between the vehicle and the electrical upfits. PSM can decrease or eliminate any additional wiring or relay logic due to its straightforward integration into onboard power supply. PSM connects directly to the body CAN and can access vehicle status information and control vehicle functions. In addition, PSM offers up to 10 inputs, both analog and digital, and 19 outputs available for user-specific components. To avoid any vehicle malfunctions on the electric control units, please never cut into or interfere with the Mercedes-Benz wiring harness (violation of Body Equipment Guidelines).

PSM uses an internal programmable logic controller (PLC), a module with freely programmable logic function blocks that freely interconnect with each other to create any requested signal links. PSM software holds a total of 12 programmable logic controller (PLC) groups, and each PLC group has 8 logic function blocks. A number of vehicle signals are available for PSM, and these signals can be combined together to create function blocks with logic combinations. The signals can connect with other signals using the following sets of logic operators and functions:

  • timer, counter, flip flop, threshold switches, threshold switches with hysteresis
  • calculating blocks, filters, differentiators/integrators, comparators, characteristics, non-volatile memory options, freely definable constants (MY2019+ Sprinters and Metris)


PSM signals in coordination with the above functionalities can create a program to improve vehicle usages such as fuel economy and vehicle and passenger safety.

PSM software is supported only by Mercedes Benz authorized personnel. PSM program must be uploaded to the vehicle via a Mercedes Benz diagnostic tool by an authorized Mercedes Benz personnel or dealer or trained eXpertUpfitter. The modes of operation for PSM differ between Sprinter and Metris. Due to software changes, MY2019 and later Sprinter models will have different PSM software than MY2018 and earlier Sprinter models. Note some PSM functions may only be available on specific vehicle models. Vehicles of the same base software type only can transfer customized PSM software dataset to other vehicles with same base software type. For more questions regarding PSM program, please contact your local dealer. Dealers and eXpertUpfitters, please log into Upfitter Portal.

PSM Technology

Examples of Vehicle Information
Vehicle Status Doors open/closed; Doors locked/unlocked; Hand brake applied
Light Status Side lamps; brake lights; turn signals; main-beam headlamps
Engine CAN Information Vehicle speed; engine speed; gear selector position; AC compressor status
Examples of Adaptable Vehicle Function
Interior/Exterior Light Activation Turn on high beams, low beams, standing lights, left and/or right turn signals
Alarm Activation Activate internal buzzer, horn, and/or hazard warning lights
Central Locking Control Lock or unlock the entire vehicle, cab section, and/or cargo section
Windshield Wipers Activate windshield wipers at different settings and speeds
Audio Mute Mute radio when for example when vehicle is in reverse or drive
Engine Start Prevention While engine is already off, engine start prevented
Text Displays on Instrument Cluster Display requested texts from a pool of available text (e.g. ‘Radio muting’, ‘High beams ON’, ‘Roofhatch OPEN’)
Power Windows Control Manual and automatic opening and closing of windows
Examples of PSM Functions
Alarm Function 1. Cargo door opens → 2. PSM provides high signal to designated output pin → 3. Pin powers aftermarket alarm
Unlock Function 1. Aftermarket button connected to PSM input activated → 2. PSM receives high input signal →3. Unlock cargo doors via PSM
Hazard Warning Lights Function 1. Aftermarket button connected to PSM input activated → 2. PSM receives high input signal → 3. Hazard Warning lights activated
Aftermarket Light Function 1. Left turn signal manually turned on → 2. PSM provides low signal to designated output pin →3. Pin powers aftermarket light