Code Definition

P0859 — Traction Control Input Signal High

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

About P0859

P0859 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 P0859 is stored, the module has detected a signal or supply voltage higher 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 P0859 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 P0859 fault code is triggered when the vehicle's control module detects a high voltage condition in the traction control input signal. This situation indicates that the voltage signal from the traction control system, which is crucial for the operation of the vehicle's stability and traction control functions, exceeds the normal operational range. A high voltage signal may be indicative of an electrical issue such as a short to power. Inaccurate or excessively high signals can impair the proper functioning of the traction control system, potentially affecting the vehicle's handling and saf...

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