DTC P0850: PNP Switch: Description

When the selector lever position is P or N, park/neutral position (PNP) signal from the TCM is sent to ECM. (A/T models)

When the selector lever position is Neutral position, park/neutral position (PNP) switch is ON. (M/T models) ECM detects the position because the continuity of the line (the ON signal) exists.