Code Definition

B103A — No or Implausible CAN Message from SAM Control Unit

System: Body  |  Type: Manufacturer-Specific  |  Make: Mercedes-Benz

About B103A

B103A is a manufacturer-specific body diagnostic trouble code recorded for Mercedes-Benz vehicles. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

Scanning & clearing: Body (B) codes are often stored in the body control module, airbag module, or climate module. A basic OBD-II tool usually will not read body codes — an enhanced or OEM-level scan tool is typically required.

B103A is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

The Signal Acquisition Module (SAM) on Mercedes Benz vehicles is a distributed control unit responsible for gathering switch, sensor, and lighting inputs and broadcasting that information to other modules over the Controller Area Network (CAN). Fault code B103A is set when the receiving control module either fails to receive an expected CAN message from the SAM within a calibrated time window, or receives a message whose content falls outside defined plausibility limits. The fault stores after a confirmed timeout or repeated data plausibility failure, indicating a disruption of CAN communicati...

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