Code Definition

P1900 — Radiator fan speed 2 circuit open or shorted to ground

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: Volkswagen

About P1900

P1900 is a manufacturer-specific powertrain diagnostic trouble code recorded for Volkswagen vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1900 is stored, the module has detected an open (broken or disconnected) electrical path in the monitored circuit; and a short-circuit (voltage pulled to ground or to supply) in the monitored circuit.

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.

P1900 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

This fault code is triggered when the engine control module (ECM) detects an open circuit or a short-to-ground condition in the radiator fan speed 2 control circuit. The radiator fan operates at multiple speeds to regulate engine temperature, and a malfunction in this circuit can lead to cooling system inefficiency, potential overheating, or increased engine temperatures.

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