Code Definition

P0494 — Cooling fan speed low

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

About P0494

P0494 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 P0494 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 P0494 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 Powertrain Control Module (PCM) sets this code when it detects that the cooling fan is operating at a lower speed than expected. This may be due to an electrical issue, a failing fan motor, or a slipping fan clutch, which can lead to inadequate engine cooling and potential overheating.

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