Code Definition

P1851 — Data Bus Drive Missing Command From ABS

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: Audi

About P1851

P1851 is a manufacturer-specific powertrain diagnostic trouble code recorded for Audi vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

P1851 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

This fault code is set when the Transmission Control Module (TCM) detects that it is not receiving the required data or command messages from the ABS control module over the drivetrain CAN bus. The ABS module supplies critical inputs such as individual wheel speeds and brake status that the TCM uses for shift logic, torque converter lockup, and stability related functions. The fault is triggered when the expected messages from the ABS module are not received within a calibrated time. The driver may notice harsh or incorrect shifting, a transmission fault or limp mode, and often related ABS or ...

Join TaT to view the complete code information and diagnostic details.

Quick Facts