The Mercedes-Benz 38 diagnostic port is a non-standard OBD-I port that allows mechanics and technicians to connect diagnostic tools to a vehicle to retrieve and clear codes from all systems including, ABS, airbag, transmission, A/C, door modules, etc. If your car has an OBD-II port and a 38-pin port, and you try to connect to the OBD-II port under the dash, all you will be able to access is the engine control unit. In other words, you will only be able to diagnose the check engine light. To access all systems you will need the 38-pin multiplexer for Mercedes-Benz.

Mercedes 140 38 port youcanic scanner all models

Mercedes-Benz models with 38-pin port

Mercedes 140 38 port loc

To diagnose other systems and lights such as ABS, SRS airbag, A/C, transmission, etc you will need to connect via the 38-pin port. The port is found on many 1990 to 2002 Mercedes-Benz models.

The following Mercedes-Benz models have the 38-pin port in the engine bay:

  • 107,
  • 124,
  • 126,
  • R129 – SL Class – All Systems Supported
  • 140 S/CL Class – All Systems Supported
  • R170 SLK-Class – All Systems Supported
  • 201,
  • 202 C-Class – All Systems Supported
  • 210 E-Class – All Systems Supported
  • 208 CLK-Class – All Systems Supported

Many of these models are supported by the YOUCANIC UCAN-II scanner. These models may also have the OBD-II port under the dash. The OBD-II port under the dashboard is used to diagnose the Engine Control Unit (ECU) and check engine light problems. The 38-pin connector is used to diagnose all other systems the vehicle may have, such as transmission, airbags, climate control, Anti-lock Brake System (ABS), traction control, etc. To access all systems, you will need to use Mercedees-Benz 38-pin multiplexer and the YOUCANIC UCAN-II scanner.

Where is the 38-pin port located on my Mercedes-Benz?

Mercedes 140 38 port

The Mercedes 38-pin diagnostic port is an OBD-I (On-Board Diagnostics version 1) interface that was used on Mercedes-Benz vehicles from the early 1990s until the early 2000s. This port is typically located under the hood of the vehicle, near the fuse box.

You will need to connect to this port to diagnose the vehicle fully. While the standard OBD-II, which allows you to diagnose the check engine light, is located under the dashboard.

Can I diagnose my 1996-2002 with YOUCANIC Scanner?

You can diagnose 1996-2002 Mercedes-Benz with a YOUCANIC scanner, but a special 38-pin adapter is required. If your Mercedes-Benz is newer than 2002 and does not have a 38-pin port, all diagnostics can be done via the OBD-II port. This video shows how to diagnose W210 E-Class and W208 CLK-Class.

Diagnosing a Mercedes-Benz 140 with the YOUCANIC scanner.

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  1. David Sederquist says:

    Need the 38 Pin for this:

    2001 Mercedes-Benz CL 600
    VIN: WDBPJ78J91A011851

    1. No 38 pin on the CL therefore no need for the multiplexer. All systems are accessed via the OBD2 port.