P0801, P0812, P0813 and P0850 to P0855: park/neutral, drive and reverse signals
The input that tells the computers the gearbox is in park or neutral, in drive, or in reverse has a fault, or so does the output that signals reverse or the circuit that blocks reverse.
SeverityModerateUsually not urgent today, but it can get worse if left.
Can you keep driving?Drive gently, check it soonWhat does P0850 mean?
The engine and gearbox computers need to know which position is selected: park or neutral to allow the starter, drive to set the idle and the gear control, reverse to light the reversing lamps, wake the camera and sensors, and on some manual gearboxes to stop reverse being selected while moving forward. Where P0705 to P0709 cover the range sensor itself, these codes cover separate switch inputs and outputs. A fault can stop the engine from starting, leave the reversing lights or camera off, or let the idle and gear control misjudge the load.
What causes P0850?
- A switch out of adjustment after gear linkage or gearbox work
- A failed park/neutral or reverse switch
- A damaged wire, or a connector full of road dirt under the car
- A reverse inhibit solenoid that is stuck or has a damaged circuit
What to check first for P0850
- Check whether the engine starts in both park and neutral
- Check that the reversing lights and camera come on in reverse
- Inspect the switch and its connector on the gearbox for dirt and damage
- Watch the switch states on a scan tool while moving through every position
Can you drive with P0850?
If the car starts only in neutral or the reversing lights do not work, you can usually drive to a workshop with care. Do not drive if the car can start in gear or creeps when it should be in park.
Since May 2018 an engine warning light that stays on is a major defect at the MOT, so the car fails until the fault is fixed.
Codes on this page
9
- P0801Reverse Inhibit Control Circuit
- P0812Reverse Input Circuit
- P0813Reverse Output Circuit
- P0850Park/Neutral Switch Input Circuit
- P0851Park/Neutral Switch Input Circuit Low
- P0852Park/Neutral Switch Input Circuit High
- P0853Drive Switch Input Circuit
- P0854Drive Switch Input Circuit Low
- P0855Drive Switch Input Circuit High
Related codes
Checked on · Rafael Soares
These are the generic meanings every manufacturer shares. Each brand adds its own detail, so your car's handbook, its service information and a qualified mechanic have the last word. OdoKeep has no connection with any manufacturer, and the app does not read codes from the car.
