Code Definition

P1817 — Transmission Neutral Safety Switch Open Circuit

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

About P1817

P1817 is a manufacturer-specific powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1817 is stored, the module has detected an open (broken or disconnected) electrical path 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.

P1817 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 is set when the Powertrain Control Module (PCM) or Transmission Control Module (TCM) detects an open circuit in the neutral safety switch circuit. The neutral safety switch provides a signal indicating that the transmission is in Park or Neutral, which is required for engine starting and for certain transmission control functions. An open circuit means there is a complete loss of electrical continuity, preventing the module from verifying the transmission range status, resulting in the setting of P1817.

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