Toyota Corolla (E120): Check and replace ecu
Notice
: start an inspection of the connector from the backside of the connector on the wire harness side with the connector connected to the ecu.
When no measurement condition is specified, perform the inspection with the engine stopped and also the ignition switch on.
- First check the ecu ground circuit. If it is faulty, repair it.
If it is normal, the ecu could be faulty. In this case, replace the ecu with one that functions normally and check if the symptoms appear.
- Measure the resistance between the ecu ground
terminal and body ground.
Resistance: 1 Ω or less

- Disconnect the ecu connector, check the ground terminals on the ecu side and wire harness side for bends and check the contact pressure.

Other materials:
Canceling and resuming the constant speed control
1 Pulling the lever toward you cancels the constant speed control.
The speed setting is also canceled when the brakes are applied or the clutch
pedal (manual transmission) is depressed.
2 Pushing the lever up resumes the constant speed control.
Resuming is available when the vehicle speed is mo ...
Trip information
■ Switching the display
Items displayed can be switched by pressing the “DISP” switch.
■ Odometer
Displays the total distance the vehicle has been driven.
Except vehicles with a manual transmission: Press and hold the “DISP” switch
to change the display to the Eco Driving ...
Circuit description
If the engine coolant temperature (ect) does not reach 75°c (167°f) despite
sufficient warm – up time has
elapsed.
Dtc no
Dtc detection condition
Trouble area
P0128
Condition (a), (b) and (c):
cold start
after engine is warmed up
& ...


