Possible causes

– Low transmission fluid level
– Dirty transmission fluid
– Faulty shift solenoid ‘D’ valve
– Shift solenoid ‘D’ valve harness or connectors
– Shift solenoid ‘D’ valve circuit is open or shorted

When is the code detected?

The P0766 code is detected when the ECM has detected a mechanical fault with the solenoid energized, valve stuck off

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– Transmission will not shift gears

P0766 HONDA Description

Shift solenoid valve ‘D’ is turned ON or OFF by the Transmission Control Module (TCM) in response to signals sent from the park/neutral position (PNP) switch, vehicle speed and Engine Control Module (ECM) (throttle opening). Gears will then be shifted to the optimum position.