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DTC codes / Nissan codes / P1797

P1797 · NissanP/N Switch Open Or Short Circuit

P1797 on a Nissan means the transmission control module (TCM) has detected an open or short circuit in the park/neutral (P/N) switch circuit, so it cannot reliably confirm whether the shifter is in Park or Neutral. The TCM monitors the switch signal and flags the code when the voltage falls outside the expected range for the current gear position.

SystemPowertrain
Code typeNissan specific
SeverityMedium
Fix difficultyIntermediate
AreaTransmission

Symptoms you may notice

  • The check engine light or transmission warning light is illuminated on the dashboard.
  • The engine may crank but not start because the TCM does not see Park or Neutral.
  • The shifter may feel normal but the starter will not engage in Park or Neutral.
  • The gear position indicator on the cluster may be blank, flashing, or show the wrong range.
  • The transmission may default to a limp or fail-safe mode with harsh or delayed shifts.
  • Often no symptoms besides the warning light, especially if the fault is intermittent.

Common causes, most likely first

  1. A failed or contaminated park/neutral switch (also called the transmission range sensor) on the side of the transaxle.
  2. A damaged, chafed, or corroded wire in the P/N switch circuit between the switch and the TCM.
  3. A loose or corroded connector at the switch or at the TCM harness.
  4. Water intrusion into the switch connector or the switch housing, common on older Nissan models.
  5. A faulty TCM that is misreading a good switch signal, though this is less common.
  6. A misadjusted switch linkage or shifter cable that prevents the switch from aligning with the selected range.

How to diagnose and fix it

  1. Scan all modules and record freeze-frame data to confirm P1797 is current and not a stored history code from a past event.
  2. Inspect the P/N switch connector and harness for corrosion, water intrusion, or chafed wires, and clean or repair as needed.
  3. Check the switch adjustment and shifter cable alignment against the service information for the specific Nissan model.
  4. Backprobe the P/N switch circuit at the TCM and compare voltage in Park, Neutral, and Drive against the factory specification.
  5. Test the P/N switch resistance or continuity through its range with a multimeter, and replace the switch if it does not switch cleanly.
  6. If the switch and wiring test good, check for a faulty TCM or a poor ground that is skewing the signal.
  7. Clear the code and perform a road test through all gear ranges to confirm the repair and that the code does not return.

P/N switch faults that fool good technicians

  • A P1797 is often set by a shifter cable that is slightly out of adjustment, so the switch never sees a true Park or Neutral even though the lever feels right.
  • Water intrusion into the switch connector on older Nissan models can cause an intermittent open circuit that only appears after rain or a car wash.
  • Technicians sometimes replace the P/N switch when the real fault is a corroded ground or a chafed wire in the harness near the transaxle mount.
  • A weak battery or poor engine ground can cause voltage spikes that the TCM interprets as a switch circuit fault, so check charging system health first.
  • The code can be stored by a momentary glitch during a low-voltage crank event, so a history-only P1797 with no drivability complaint may not need parts.

Can I keep driving with P1797?

You can usually drive the vehicle if it starts and moves, but avoid relying on Park or Neutral for starting and have the fault checked promptly. If the engine will not crank in Park or Neutral, do not force the shifter or bypass the switch; have the vehicle towed or repaired before driving.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for Nissan vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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