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 support system
information display
■ Driving support system
information
Select to display the operational
status of the following systems:
Dynamic radar cruise control
LTA (Lane Tracing Assist)
LDA (Lane Departure Alert)
■ Navigation system-linked
display (if equipped)
Select to display the following
navigation system-linked ...
Using automatic mode
1 Press .
The dehumidification function begins to operate. Air outlets and fan speed are
automatically adjusted according to the temperature setting.
2 Adjust the temperature setting.
3 To stop the operation, press again.
■ If the system is operated manually in automatic mode
If the fa ...
Circuit description
Refer to dtc p0115
Dtc no.
Dtc detection condition
Trouble area
P0125
If the engine coolant temperature (ect) was less than –6.6 °C
(20 °F) when starting the engine, and 20 minutes after the engine
start, the ect sensor still indicates below 20 °C (68 ...


