Possible causes

– Low transmission fluid level
– Dirty transmission fluid
– Faulty shift solenoid ‘E’ valve
– Shift solenoid ‘E’ valve harness is open or shorted
– Shift solenoid ‘E’ valve circuit poor electrical connection

Tech notes

There is a factory service bulletin for the following models:

2003 Toyota Corolla
2003 Toyota Matrix
2003 Toyota Factory Service Bulletin OBDII Code P0770

When is the code detected?

The P0770 code is detected when Lock up does not occur when driving in the lock up range (normal driving at 80 km/h [50 mph]), or lock up remains ON in the lock up OFF range.

Symptoms

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

P0770 TOYOTA Description

The ECM uses the signals from the Throttle Position Sensor and Air flow Meter to monitor the engagement condition of the lock up clutch. Then the ECM compares the engagement condition of the lock up clutch with the lock up schedule in the ECM memory to detect mechanical trouble of the shift solenoid valve SLU, valve body, torque converter clutch and automatic transmission assembly

TOYOTA Technical Service Bulletins for P0770 code