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:
Inspection procedure
1 Inspect transmission wire(sl)
Disconnect the transmission wire connector from the
transaxle.
measure the resistance according to the value(s) in the
table below.
Standard:
2 Check harness and connector(transmission wire – ecm)
Connect the transmission wire c ...
Circuit description
The ignition switch provides circuit power and the ecm provides the circuit
ground that illuminates the mil.
Mil operation is checked visually:
it should be illuminated when the ignition is first turned on. If the mil is off
all of the time or on all of the time,
use the procedure below to ...
Pre–check
1. Selecting compass display mode
the compass switch allows you to select the display or non–display
mode of the compass.
2. Setting zone
deviation between the ”magnetic north” and ”actual north” differs
depending on the location. Therefore,
adjustment of the ...


