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:
Using the key (vehicles
without a smart key system
and with a wireless
remote control function)
Releasing
To release the key, press the button
Folding
To stow the key, press the button
then fold the key.
Using the mechanical key
(vehicles with a smart key
system)
To take out the mechanical key,
slide the release button and take
the key out.
The mechanical key can only be
inserted in o ...
Adjustment
Hint:
in the rh side, work in the same procedure as in the lh
side.
Since the centering bolt is used as a door side hinge bolt,
the door hinge cannot be adjusted with it on. Substitute
the bolt with washer for the centering bolt.
1. Inspect front door panel sub–assy lh
Che ...
Symptom confirmation and diagnostic trouble code
Hint:
the diagnostic system in corolla has various functions. The first
function is the diagnostic trouble
code (dtc) check, in which a malfunction in the signal circuits to the ecu
is stored in code form in
the ecu memory. Another function is the input signal check, which checks if
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