Code Definition

P0A85 — Hybrid battery pack cooling fan 1 circuit high

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

About P0A85

P0A85 is a generic (obd-ii standard) powertrain diagnostic trouble code recorded for Toyota vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P0A85 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 P0A85 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

This DTC sets when the battery ECU detects an abnormally high voltage condition in the Cooling Fan 1 control circuit. This typically indicates an open circuit, a short to power, or a malfunction in the fan driver or feedback line. The ECU monitors the voltage level of the fan control signal or feedback line, and if it exceeds a calibrated threshold while the fan is commanded off or operating at a lower speed, the fault is logged.

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