P0850: Park/neutral switch input circuit fault
Park/neutral position switch input circuit
Severity: Inspect soon
Kelley Blue Book calls P0850 serious because the engine may not start, and TroubleCodes.net says it can lock out cruise control.
It gets more serious if:
- Not verified: The shifter position does not match the gear you selected, or the car will not leave Park. We found no source saying whether you can keep driving.
P0850 in short
P0850 means the computer is getting a bad signal from the park/neutral position switch, which tells it whether the gear selector is in Park or Neutral. A misadjusted switch, water or corrosion, or wiring can cause it. The car may not start, so have it inspected soon.
The park/neutral switch tells the engine computer when the car is in Park or Neutral. The engine will normally start only in those positions, and cruise control may also use the signal.
TroubleCodes.net says the fault is often corrosion or water in the switch, misalignment or an aftermarket remote starter. Kelley Blue Book adds a misadjusted range sensor, loose bolts, damaged wiring and liquid near the shifter.
Some bulletins list P0850 among other codes. Ford has one for intermittent or delayed engagement on the 2012-2013 Focus, and Land Rover has one for a Range Rover Sport that would not leave Park.
Most likely causes
These are general causes for this code across vehicles. None is specific to one make or model.
Cause 1: Misadjusted or loose range switch
Common general cause- Why it ranks here
- Kelley Blue Book and TroubleCodes.net both list misalignment, and Kelley Blue Book adds loose mounting bolts.
- What would change this
- Rises if the car starts only with the shifter wiggled, or the switch was recently disturbed.
Cause 2: Water or corrosion in the switch or connector
Common general cause- Why it ranks here
- TroubleCodes.net lists corrosion or water, and Kelley Blue Book lists liquid damage.
- What would change this
- Rises if there was a spill near the shifter, a wash or a leak into the connector.
Cause 3: Damaged wiring or connector
Common general cause- Why it ranks here
- Both sources list wiring faults.
- What would change this
- Rises if the harness is chafed or the connector is loose.
Cause 4: Failed switch
Common general cause- Why it ranks here
- Kelley Blue Book lists the switch itself.
- What would change this
- Rises if alignment and wiring test good and the signal still does not follow the shifter.
Cause 5: Aftermarket remote starter or alarm
Common general cause- Why it ranks here
- TroubleCodes.net lists an aftermarket remote starter as a cause.
- What would change this
- Rises if one was fitted before the code appeared.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: Read codes from the engine and transmission modules with a scan tool that supports both, before anything is cleared.
IfOther transmission or shifter codes are stored
It meansLook for a shared wiring or switch fault.
IfP0850 alone
It meansCheck for aftermarket accessories.
Step 2: Check whether an aftermarket remote starter or alarm was installed, and whether liquid has reached the shifter area.
IfA remote starter was installed
It meansHave the installer check its park/neutral connection.
IfLiquid or corrosion near the shifter or connector
It meansWater damage is likely.
IfNeither
It meansCheck the switch adjustment.
Step 3: Check the switch mounting bolts and alignment, and its wiring, against the maker's procedure.
Warning:Work with the engine off, the parking brake set and the wheels blocked. A switch adjustment changes when the engine can start.
IfLoose or out of alignment
It meansReadjust it to the maker's mark and retest.
IfWiring is damaged
It meansRepair the wiring.
IfAlignment and wiring look fine
It meansHave a shop test the switch signal.
Step 4: Have a shop test the switch with a meter for continuity and signal in each shifter position.
Warning:Shop test. It needs the maker's wiring diagram.
IfThe signal does not follow the shifter and the wiring is good
It meansThe switch has failed.
IfThe signal is correct
It meansRecheck the wiring and any aftermarket accessory.
Symptoms
- Check engine light
- Cruise control stops working
- Engine does not start, or starts only in Neutral
- Intermittent or delayed gear engagement
- Cannot shift out of Park Gets more serious: stop and have it checked.
How to fix
Step 1: Do not clear the code before the transmission module has been read.
Step 2: If a remote starter was fitted recently, have the installer check it first.
Step 3: Keep drinks and liquids away from the shifter area, and look for signs of a past spill.
On your vehicle
FordYour car
2012–2013 · Focus
Supported by vehicle dataFord ASI 44686 covers intermittent or delayed engagement with a list of powertrain codes that includes P0850. The bulletin is on NHTSA, but whether it is still current is not verified, so it is labelled vehicle data rather than confirmed.
ASI 44686Status unverified
Intermittent or delayed engagement with powertrain codes including P0850
2012–2013focus · NHTSA 10056788
Ford covers 2012-2013 Focus cars with an intermittent or delayed engagement, with or without powertrain codes, P0850 among them. Only the NHTSA flat-file summary was reviewed, not the bulletin itself.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
Land RoverYour car
2014 · Range Rover Sport
Supported by vehicle dataLand Rover LTB00677NAS1 covers a car that cannot shift out of Park, with a Gearbox Fault message and several codes including P0850. The bulletin is on NHTSA, but whether it is still current is not verified, so it is labelled vehicle data rather than confirmed.
LTB00677NAS1Status unverified
Cannot shift out of Park, Gearbox Fault message
2014range-rover-sport · NHTSA 10101662
Land Rover covers a 2014 Range Rover Sport that cannot be shifted out of Park and shows a Gearbox Fault message, with several codes including P0850. Only the NHTSA flat-file summary was reviewed, not the bulletin itself.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
Related codes
No curated relationships for P0850 yet.
P0850 questions
Why would P0850 stop my car from starting?
The engine computer uses the park/neutral switch to allow starting only in Park or Neutral. A bad signal can make it think the car is in gear, so it will not crank.
Is P0850 serious?
Kelley Blue Book calls it serious because the car may not start, while TroubleCodes.net mainly notes lost cruise control. Have it inspected soon.
Sources and review
- P0850 Code: Park/Neutral Switch Input Circuit
- P0850 Trouble Code: Park/neutral switch input circuit
- LTB00677NAS1: Transmission unable to shift from Park, Gearbox Fault message
- ASI 44686: Intermittent or delayed engagement, DTCs including P0850
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error