P0850
ŚredniMalfunction in the Park/Neutral Position (PNP) switch input circuit. The PCM controller is not receiving a correct signal about the transmission position.
OBD-II (EN): Park/Neutral Position Switch Input Circuit Malfunction
Code P0850 indicates a problem with the Park/Neutral Position switch circuit – a component that informs the vehicle's computer about the current position of the transmission lever. The fault may manifest as difficulty starting the engine or incorrect automatic transmission operation. The cause could be a worn switch, damaged wiring harness, or an adjustment issue – diagnosis at a workshop with access to an OBD scanner and electrical diagrams is recommended.
Symptoms
• Engine does not start or starts with difficulty (start-in-gear protection) • Inability to start the engine in P or N position • Check Engine Light (MIL) illuminated • Transmission may not shift correctly • In some vehicles, no reverse lights • Incorrect engine management system operation (altered ignition timing, mixture composition)
Possible causes
• Damaged or worn Park/Neutral Position switch (PNP / neutral safety switch) • Open or short circuit in the switch circuit wiring • Damaged or corroded sensor electrical connector • Incorrect adjustment (calibration) of the PNP switch • Faulty PCM/ECM controller (rare)
Affected systems
Sources and further reading
Does code P0850 require professional diagnostics?
The code alone is not enough. To find the cause, you need to read live data, check freeze frame conditions, and compare with vehicle behavior. Book a diagnostic session.