Code Definition

P1819 — Neutral Safety Switch input short to ground

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

About P1819

P1819 is a manufacturer-specific powertrain diagnostic trouble code recorded for Ford vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1819 is stored, the module has detected 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.

P1819 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 DTC sets when the powertrain control module (PCM) or 4WD control module detects a short to ground on the neutral safety switch input circuit. The module uses this input to verify the transmission gear position, particularly during 4WD range shifts and engine start authorisation. If the signal voltage drops below the valid range from a short to ground, the module cannot confirm the gear state and logs the fault. The driver may experience no crank in Park or Neutral, restricted 4WD range shifting, or an incorrect gear position display.

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