What P0850 means
The park/neutral input tells the engine control module whether the automatic is in P or N, or a manual transmission in neutral.
How the engine computer detects it
It releases the starter, prepares idle control for the load of an engaged gear and enables cruise control and other monitors. All documented makers check it for plausibility against driving state or a second source such as the transmission module. On GM's 6T70 and Subaru the switch pulls the line to ground in P/N. P0850 is the general fault. Ford's 2023 diesels check the switch for plausibility at start-up and set the code after 1 s. On GM's 6T70, as in the Saab 9-4X, the module sees P/N while the range switch reports a gear for 0.2 s above 10 km/h (6 mph) and 75 Nm (55 lb-ft), type C without MIL; it then uses the range switch for start release.
Written from public technical sources and not yet checked by a mechanic. How we write these pages
Symptoms
- Engine does not crank in P or N
- Engine cranks in a drive range (safety risk)
- Rough or wrong idle
- Cruise control not working
Common causes
- Range or inhibitor switch faulty or misadjusted Most likely
- Selector cable misadjusted or stretched Possible
- Wiring or connector between switch, transmission module and engine module Possible
- Module input or software Less likely
How to diagnose P0850
- Read every stored code with an OBD-II scanner. If misfire or fuel trim codes are there too, fix those first: they often cause this one.
- Inspect the parts involved: park neutral switch, transmission range sensor, switch wiring, engine control module.
- Work through the causes above from most to least likely, cheapest checks first.
- Clear the code and drive a full drive cycle to confirm the repair held.
Vehicles that report P0850 most
| Vehicle | Years | Reports | Share | Median miles |
|---|---|---|---|---|
| Nissan Pathfinder | 2007–2014 | 3 | — |
Counts of owner complaints to the NHTSA that mention P0850 (7 in total), not failure rates: popular models get more complaints simply because more of them are on the road. Models with fewer than 3 complaints are left out.
Reading the code
- P
- Powertrain
- 0
- Generic (SAE) code
- 8
- Transmission
- 50
- Specific fault
Questions drivers ask
Can I drive with code P0850?
If the car shifts normally, drive gently to a shop. If it's stuck in one gear, slips, shifts harshly or won't move out of Park, don't drive it: have it towed.
Will my car pass an emissions inspection with P0850?
Probably not in states that test vehicles with an OBD-II scan: an emissions-related code that keeps the check engine light on is usually an automatic fail. Rules differ by state and county, so check yours.
This page is general information, not a substitute for a professional diagnosis. Repair costs are rough estimates for parts and labor and vary by vehicle and region.