01 Cruise Control: Understanding Its Functionality and Best Pr… • 02 What to Do If Your Electric Car Runs Out of Charge in the M… • 03 Can a Dirty Air Filter Cause a Check Engine Light? Yes, and… • 04 Step-by-Step: How to Safely Remove Paint from Car Windows P… • 05 Should You Admit Fault in a Car Accident if It's Your Fault? • 06 How to Choose the Right SUV: A Comprehensive Guide • 07 Starting A Car Dealership Business: What You Need To Know • 08 How to Jumpstart Your Car: A Step-by-Step Guide • 09 Types of Chain Drives: Uses, Design, Application, Pros, and… • 10 The Fastest Way to Diagnose a No-Start Problem •

DTC codes / P08xx · Transmission / P086C

P086CNeutral Position Sensor A Circuit Low

P086C means the transmission control module (TCM) has detected a low-voltage condition on the signal circuit for the neutral position sensor, also called the transmission range sensor. The computer expects a voltage within a specific range when the shifter is in neutral, but the signal is below the minimum threshold, so it flags the circuit as faulty.

SystemPowertrain
Code typeGeneric (all makes)
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 recognize neutral or park.
  • The gear indicator on the instrument cluster may be blank, flashing, or show the wrong range.
  • The transmission may refuse to shift out of park or may engage harshly when selecting a gear.
  • In some vehicles, the reverse lights may fail to operate or the backup camera may not activate.
  • Often no symptoms besides the warning light, especially if the fault is intermittent.

Common causes, most likely first

  1. A faulty neutral position sensor or transmission range sensor internal failure.
  2. Damaged, chafed, or corroded wiring in the sensor signal circuit, often near the transmission case or connector.
  3. A poor electrical connection at the sensor harness connector, including loose pins or water intrusion.
  4. A short to ground on the signal wire between the sensor and the TCM.
  5. A failed TCM or a software issue in the TCM that misreads the sensor voltage.
  6. Improper sensor adjustment or installation after previous transmission work.
  7. Extreme contamination or debris buildup on the sensor face preventing correct signal generation.

How to diagnose and fix it

  1. Scan all modules for stored and pending codes, and record freeze-frame data to see when the fault occurred.
  2. Visually inspect the neutral position sensor connector and wiring for damage, corrosion, or loose pins.
  3. Check the sensor signal voltage with a multimeter while moving the shifter through the ranges, comparing to the manufacturer's specification.
  4. Perform a voltage drop test on the signal circuit to rule out high resistance in the wiring or connectors.
  5. If the signal is low only at the sensor, remove and inspect the sensor for mechanical damage or misalignment, then reinstall or replace it.
  6. If the wiring and sensor check out, test the TCM input circuit and verify the TCM is not misinterpreting a correct signal.
  7. Clear the codes and perform a relearn or calibration procedure if required by the manufacturer, then road test to confirm the repair.

What the neutral sensor code hides

  • A low voltage on the neutral position sensor circuit often comes from a simple chafed wire near the transmission mount or exhaust, not from a failed sensor, so always inspect the harness before replacing parts.
  • Some vehicles use the same sensor for backup lights and shift interlock, so a P086C may appear together with inoperative reverse lamps or a shifter that will not release from park.
  • The TCM may set P086C intermittently when the battery voltage is low or the charging system is weak, because the reference voltage to the sensor drops below the expected threshold.
  • After transmission replacement or clutch work, the neutral position sensor can be slightly misaligned, producing a low signal only in certain shifter positions and setting this code without any driveability complaint.
  • A code P086C does not always mean the sensor is dead; a shorted signal wire or a faulty TCM driver can pull the voltage low, so circuit testing is essential before parts replacement.

Can I keep driving with P086C?

If the vehicle starts and drives normally, you can drive it to a repair shop, but avoid relying on remote start or the shifter interlock until the fault is fixed. If the engine will not crank or the transmission will not engage gears, do not continue driving and have the vehicle towed.

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 all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

Running on fumes Free guides aren't free to make. Top up the tank. Any amount, one time. Fuel the Garage