Possible Causes

WARNING: This page is about a different car, the 2003 Toyota Camry. However, it is still accessible from the selected car via links, so may be relevant.

Possible causes are:

DTC P0705

Two or more switches are ON simultaneously for N, 2, L and R positions (2 trip detection logic).

DTC P0850

When driving with vehicle speed 43 mph (70 km/h) or more and engine speed between 1500-2500 RPM for 30 seconds or more park/neutral position switch is ON (N position). (2 trip detection logic).
Short in park/neutral position switch circuit.
Defective park/neutral position switch.
Defective ECM.

After confirming DTC P0705 and P0850, use the hand-held tester to confirm the park/neutral position switch signal from the DIAGNOSIS/ENHANCED OBD II/DATA LIST/ALL DATA.