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:
Keys
The following keys are provided
with the vehicle.
Type A
Keys (without a wireless
remote control function)
Key number plate
Type B
Keys (with a wireless remote
control function)
Operating the wireless remote control
function
Key number plate
Type C
Electronic keys
Operating the sm ...
Diagnostic trouble code chart
Terms
Terms
Physical address
Three–digit code (shown in hexadecimal) which is given to each
component comprising
the avc–lan.
Corresponding to the function, individual symbols are specified.
Logical address
Two–digit code (shown in hexadeci ...
Circuit description
In the diagram below, when the engine is cranked, current flows from terminal
st2 of the ignition switch to
the starter relay coil and also current flows to terminal sta of the ecm (sta
signal).
When the sta signal and ne signal are input to the ecm, tr is turned on, current
flows to the c ...


