Code Definition

P0958 — ASM Mode Circuit High

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

About P0958

P0958 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 P0958 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 P0958 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 P0958 fault code is set when the control module detects a high voltage condition in the ASM (Adaptive Shift Control) mode circuit. This circuit facilitates the selection of different transmission modes, such as performance, winter, or sport modes, each adjusting the transmission's shifting behaviour to suit varying driving conditions and preferences. A high voltage condition in this circuit typically indicates an electrical fault, such as a short to power or a problem within the mode selection components like switches or sensors. High voltage can lead to malfunctioning of the transmission ...

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