Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.
For the CVT transmission the Park/Neutral Switch is located inside the shifter assembly, for the manual transmission it is located on the transmission (see picture)
The cost to diagnose the P0850 2009 Nissan Altima Sedan code is 1.0 hour of labor. The auto repair's diagnosis time and labor rates vary by location, vehicle's make and model, and even your engine type. Most auto repair shops charge between $75 and $150 per hour.
The signal of the park/neutral position (PNP) switch is not changed in the process of engine starting and driving.
When the shift position is P or N, Park/Neutral Position (PNP) switch is turned ON. The Engine Control Module (ECM) detects the position because the continuity of the line (the ON signal) exists.
The Park/Neutral Position (PNP) switch assembly also indicates a transmission range switch to detect shift lever position.
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