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.
Medium severity. Can I keep driving?Drive gently to a repair shop. If it slips, you hear clunks, or it loses its gears, do not keep driving.
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
Most likely causes
- Range or inhibitor switch faulty or misadjusted
- Selector cable misadjusted or stretched
- Wiring or connector between switch, gearbox module and engine module
- Module input or software
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P0850 means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- 8: Transmission
- 50: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0850?
Drive gently to a repair shop. If it slips, you hear clunks, or it loses its gears, do not keep driving.
What causes code P0850?
The most common causes are: range or inhibitor switch faulty or misadjusted; selector cable misadjusted or stretched; wiring or connector between switch, gearbox module and engine module.
Related codes
- P0851Park/Neutral Switch Input Circuit Low
- P0852Park/Neutral Switch Input Circuit High
- P084FPark/Neutral Switch Output Circuit
- P0705Transmission Range Sensor A Circuit (PRNDL Input)
- P081CPark Input Circuit
- P0853Drive Switch Input Circuit
Sources
- fordservicecontent.com: obd summary diesel 2023
- saabwisonline.com: dtc p0850 p0852
- static.nhtsa.gov: MC 10237505 0001
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.