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:
Circuit description
The fuel trim is related to the feedback compensation value, not to the basic
injection time. The fuel trim includes
the short–term fuel trim and the long–term fuel trim.
The short–term fuel trim is the short–term fuel compensation used to maintain
the air–fuel ratio at stoichiomet ...
Problem symptoms table
If a normal code is displayed during the dtc check but the problem still
occurs, check the circuits for each
problem symptom in the order given in the table below and proceed to the
relevant troubleshooting page.
Notice:
when replacing skid control ecu, sensor or etc., Turn the ignition swi ...
Inspection procedure
1 Check relay (marking: starter cut)
Inspect the relay continuity, as shown in the illustration
and table.
Standard:
2 Check tvip ecu
Disconnect the tvip ecu connector.
turn the ignition switch position to the start.
measure the voltage between the termina ...


