Damaged, corroded, or disconnected wiring or connector at the neutral position sensor; Faulty neutral position sensor itself (internal open circuit); Poor electrical connection at the transmission control module (TCM) or powertrain control module (PCM); Open circuit in the sensor ground or signal return wire; Contamination or mechanical damage to the sensor or its mounting area; Aftermarket or improperly installed remote start or alarm system interfering with the neutral signal circuit

DTC codes / P08xx · Transmission / P086A

P086ANeutral Position Sensor A Circuit/Open

Q: What does code P086A mean?

Neutral Position Sensor A Circuit/Open. P086A means the transmission control module (TCM) has detected an open circuit or loss of signal on the 'A' neutral position sensor circuit, which is used to confirm the transmission is in neutral. The computer sets this code when the voltage on that circuit falls outside the expected range for the current gear or when the signal is missing entirely.

P086A means the transmission control module (TCM) has detected an open circuit or loss of signal on the 'A' neutral position sensor circuit, which is used to confirm the transmission is in neutral. The computer sets this code when the voltage on that circuit falls outside the expected range for the current gear or when the signal is missing entirely.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaTransmission

Symptoms you may notice

Illuminated check engine light or transmission warning light, often with no other symptoms
Harsh or delayed shifting, especially when selecting drive or reverse
Transmission may default to a limp-home mode or stay in a single gear
Engine may crank but not start if the neutral signal is required for starting
Incorrect or missing gear position display on the instrument cluster
Occasional no-start condition when the vehicle is not recognized as being in park or neutral

Common causes, most likely first

Damaged, corroded, or disconnected wiring or connector at the neutral position sensor
Faulty neutral position sensor itself (internal open circuit)
Poor electrical connection at the transmission control module (TCM) or powertrain control module (PCM)
Open circuit in the sensor ground or signal return wire
Contamination or mechanical damage to the sensor or its mounting area
Aftermarket or improperly installed remote start or alarm system interfering with the neutral signal circuit

How to diagnose and fix it

Inspect the neutral position sensor connector and wiring for corrosion, chafing, or loose pins, and repair as needed
Check the sensor circuit for continuity and voltage drops with a multimeter, comparing to manufacturer specifications
Test the neutral position sensor resistance or voltage output through its full range of motion and replace if out of specification
Verify power and ground at the TCM/PCM connector and clean or repair terminals if necessary
Clear the code and perform a relearn or calibration procedure if required by the vehicle manufacturer
If the code persists, perform a pinpoint test for the neutral position sensor circuit using a factory scan tool and wiring diagram
Replace the neutral position sensor only after electrical tests confirm it is faulty, then clear codes and verify repair

Neutral sensor circuit checks before replacement

A loose or corroded connector at the neutral position sensor is far more common than a failed sensor, so always inspect and wiggle-test the harness first.
This code can be set by a weak battery or poor ground connection that causes voltage spikes or drops on the sensor circuit, so check battery and grounds before condemning parts.
Some vehicles use the neutral position sensor signal for both starting and shift quality, so a fault can cause a no-crank condition that is misdiagnosed as a starter or ignition switch problem.
Aftermarket remote start systems that tap into the neutral safety circuit often introduce opens or false signals, so check for non-factory wiring before assuming a factory defect.
The code may appear intermittently if the sensor is only failing when hot or when the transmission is in a specific gear, so road-test with a scan tool recording live data to catch the dropout.

Can I keep driving with P086A?

The vehicle may be safe to drive short distances if it shifts normally and starts reliably, but avoid aggressive acceleration or towing until the fault is repaired. If the transmission is in limp mode or the engine will not start, do not drive and have the vehicle towed to a repair shop.

Tools that help

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