What it means
The neutral position sensor A reports a circuit/open fault. Verification of true neutral position is impaired.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Neutral position sensor A reports whether the transmission is in neutral so the TCM can verify the selected range. P086A sets when the sensor A circuit is open, leaving the module without a dependable electrical signal to confirm neutral.
Common causes
Most likely first.
- Position sensor failed
- Wiring fault
- Pin pushed back out of connector body
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
How to diagnose it
- Save freeze-frame data and check live neutral-position status while selecting each range, noting whether sensor A stays unavailable or fails to change.
- With the vehicle secured, inspect sensor A’s connector for a loose plug, pushed-back pin, corrosion, or water entry.
- Trace the sensor A wiring for breaks, chafing, or damage near the transmission and repair visible faults.
- Check circuit continuity and the sensor’s power, ground, and signal paths using the wiring diagram and manufacturer’s procedure.
- If the wiring and connections pass, test sensor A and replace it only if it fails the specified checks.
Common fixes
- Seat the connector fully and correct any pushed-back or damaged terminal.
- Repair an open or damaged section of sensor A wiring.
- Clean or replace corroded connector terminals as appropriate.
- Replace neutral position sensor A if it fails testing.
Can I keep driving?
Because the TCM may not reliably recognize neutral, the vehicle may shift abnormally or enter limp mode. Avoid driving if gear selection is uncertain or the vehicle moves unexpectedly in neutral; arrange repair promptly.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.