Possible causes

– Low transmission fluid level
– Dirty transmission fluid
– Faulty pressure control solenoid valve ‘C’
– Pressure control solenoid valve ‘C’ harness is open or shorted
– Pressure control solenoid valve ‘C’ circuit poor electrcial connection

When is the code detected?

Engine Control Module (ECM) detectes an open or shorted condition on the solenoid circuit

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– Shift shock

P0798 SCION Description

The Engine Control Module (ECM) uses signals from the vehicle speed sensor to detect the actual gear position (1st, 2nd, 3rd, 4th or 5th gear). Then the ECM compares the actual gear with the shift schedule in the ECM memory to detect mechanical troubles of the shift solenoid valves and valve body.