Code Definition

P0978 — Shift Solenoid C Control Circuit Range/Performance

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

About P0978

P0978 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 P0978 is stored, the module has detected a plausibility fault — the measured value is in the electrical range but is not consistent with expected operating behaviour.

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 P0978 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 P0978 fault code is activated when the control module detects a range or performance issue in the control circuit of Shift Solenoid C. This solenoid plays a vital role in automatic transmissions, controlling the flow of hydraulic fluid necessary for the engagement or disengagement of gears. A range or performance problem in this circuit suggests that the operation of Shift Solenoid C or its control circuit is not within the manufacturer's specified parameters or is not functioning effectively. Causes could include a malfunctioning solenoid, issues with the wiring, or problems within the Tr...

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