P0850 means Park/Neutral Switch Input Circuit. The computer is not seeing the expected signal from the park/neutral position switch, so it cannot tell when the transmission is in park or neutral. It is a generic OBD-II code, so the definition is the same on any make, but the most likely cause varies by engine; confirm with a scan tool and the service information for your vehicle before buying parts.
What P0850 means
Electronically controlled automatics are run by a transmission control module (TCM), a separate box or part of the engine computer. It reads speed sensors, the range sensor and fluid temperature to decide when to shift, and drives solenoids that apply clutches and the torque converter clutch. Many basic code readers only show the generic P0700; a scan tool that reads the transmission module shows the specific fault. Check fluid level and condition first, since low or burnt fluid causes many transmission codes.
P0850 symptoms
- Engine will not crank in park or neutral
- Engine cranks in gear on some vehicles
- Idle changes when shifting
- Check engine light
Common causes of P0850
- Misadjusted or failed switch or range sensor
- Wiring or connector fault
- Shift linkage out of adjustment
How to diagnose P0850
- Watch the park/neutral input on a scan tool while moving the shifter
- Check switch adjustment
- Inspect the connector and wiring
Can you drive with P0850?
Use caution: make sure the engine will not start in gear.
P0850 tips
On many vehicles the park/neutral switch is part of the range sensor; adjust it to specification after any transmission work.
Will P0850 clear itself?
If the fault stops, the computer turns off the check engine light by itself after several drive cycles without seeing it again, and the code stays in memory as history for a while. Clearing P0850 with a scan tool after a repair is fine, but if the cause is still there the code returns, sometimes within one drive. Disconnecting the battery also clears codes on most vehicles, but it erases learned fuel trims and idle settings as well.
Related codes
| Code | Meaning |
|---|---|
| P0705 | Transmission Range Sensor Circuit Malfunction (PRNDL Input) |
| P0706 | Transmission Range Sensor Circuit Range/Performance |
| P0707 | Transmission Range Sensor A Circuit Low |
Guides that help
When it is more than a sensor
If the fault turns out to be internal (worn clutches, a failed converter or a damaged valve body), compare a rebuild with a replacement in transmission rebuild vs replacement and transmission replacement cost, identify your unit with what transmission do I have?, and browse our transmissions.
Shipping is a flat $80.00 per order to US addresses, with 15-day free returns. Questions? Ask a parts specialist.