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:
How to proceed with troubleshooting
Troubleshoot in accordance with the procedure on the following pages.
1 Vehicle brought to workshop
2 Customer problem analysis check and symptom check
Without applicable symptoms, proceed to ”a”.
with applicable symptoms, proceed to ”b”.
3 Symptom simulation
4 Prob ...
Starting the engine
► Automatic transmission or continuously
variable transmission
1 Check that the parking brake is set.
2 Check that the shift lever is set in P.
3 Firmly depress the brake pedal.
4 Turn the engine switch to the “START” position and start the engine.
► Manual transmission
1 Che ...
Follow the correction procedures. (vehicles with a smart key system and with
a drive monitor display)
After taking the specified steps to correct the suspected problem, check that
the warning light turns off.
■SRS warning light
This warning light system monitors the airbag sensor assembly, front impact
sensors, side impact sensors (front door), side impact sensors (front), side impac ...


