Is It Safe to Drive With a P0850 Code?
Common Symptoms of a P0850 Fault
EML on
Car may not start in park or neutral
Starter may operate in gear (safety concern)
Idle speed may be incorrect
Possible Causes of P0850
A P0850 code can be triggered by faults across several systems. Identifying the exact root cause requires proper diagnostic equipment and live data — not just reading the code.
Park/Neutral Switch Wiring Fault
Wiring to the park/neutral switch is damaged.
Park/Neutral Switch Failure
The switch itself has failed.
Selector Linkage Issue
Gear selector linkage not actuating the switch correctly.
ECU Input Fault
ECU input circuit for the park/neutral switch.
Why we don't list the exact part: A P0850 code tells you what's happening but not why. Replacing parts based on the code alone is the most common way drivers waste money. A proper diagnosis identifies the specific cause first.
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P0850 and Your MOT
A stored P0850 fault code will cause your car to fail its MOT. The engine management light will be illuminated during the test — an automatic failure under current MOT standards. Even if the light temporarily clears, the code remains in ECU memory and can be read by testers.
Get the fault diagnosed and repaired first, then have the code cleared and confirm the light stays off before booking your MOT.