P0850 code meaning
Park/Neutral Switch Input Circuit
What P0850 means
The park/neutral input tells the engine control module whether the automatic is in P or N, or a manual gearbox in neutral. 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 gearbox 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 and 75 Nm, type C without MIL; it then uses the range switch for start release.
P0850 at a glance
- Check engine lightUsually not
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0850
- 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 of P0850
- Most likelyRange or inhibitor switch faulty or misadjusted
- PossibleSelector cable misadjusted or stretched
- PossibleWiring or connector between switch, gearbox module and engine module
- Less likelyModule input or software
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Park neutral switchTransmission range sensorSwitch wiringEngine control module
What each part of P0850 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 8 | Area: transmission. |
| 50 | The exact fault in that area. |
What to do next
- Note P0850 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0850
What does P0850 mean?
P0850 means "Park/Neutral Switch Input Circuit". The park/neutral input tells the engine control module whether the automatic is in P or N, or a manual gearbox in neutral. It is a generic code, so it means the same on every make.
Is it safe to drive with P0850?
P0850 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will P0850 fail an emissions test?
Yes, it can. P0850 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0850 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. This is a job for a workshop.
Will P0850 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.