Code Definition

P0861 — Gear Shift Module Communication Circuit Low - Circuit A

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P0861

P0861 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P0861 is stored, the module has detected a signal or supply voltage lower than the expected operating range.

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.

Because P0861 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The P0861 fault code is activated when the vehicle's control module detects a low voltage condition in the communication circuit of the Gear Shift Module, specifically in Circuit A. This low voltage condition suggests that the signal in the gear shift module's communication circuit is below the normal operational range, potentially pointing to an electrical problem such as a short to ground. A low voltage in this circuit can impair the effective communication and operation of the gear shift module, which could adversely affect the vehicle's gear selection and transmission performance.

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