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:
Driving assist systems
To help enhance driving safety and performance, the following systems operate
automatically in response to various driving situations. Be aware, however, that
these systems are supplementary and should not be relied upon too heavily when operating
the vehicle.
◆ ABS (Anti-lock Brake Sys ...
Warning lights
Warning lights inform the driver of malfunctions in the indicated vehicle’s systems.
*1: Vehicles without a smart key system:
These lights turn on when the engine switch is turned to the “ON” position to indicate
that a system check is being performed. They will turn off after the engi ...
Inspection procedure
1 Check operation(starter)
Check that the starter operates normally and that the engine starts.
2 Input signal check
See input signal check on page 05–745.
check the indicator light when shifting into except d position.
Ok:
the indicator light goes off when shifting ...


