Possible causes

– Low transmission fluid level
– Shift solenoid mechanical fault
– Hydraulic circuit fault
– Transmission failure

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– Transmission will not shift into 6th gear

P0729 INFINITI Description

This malfunction is detected when the A/T does not shift into 6GR position as instructed by TCM. This is not only caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.