Possible causes

– Low transmission fluid level
– Dirty transmission fluid
– Faulty Shift Pressure Solenoid valve
– Shift Pressure Solenoid valve harness is open or shorted
– Shift Pressure Solenoid valve circuit poor electrical connection

When is the code detected?

The TCM has detected voltage on the shift pressure solenoid during a period when the solenoid is not active

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– Transmission shift shock

P0778 JEEP Description

The shift pressure solenoid valve regulates the oil pump discharge pressure to suit the driving condition in response to a signal sent from the Transmission Control Module (TCM).