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:
Malfunction in tachometer
Wiring diagram
Inspection procedure
Check output value of ecm.
Connect the hand–held tester to dlc3.
Turn the ignition switch to on and push the hand–held tester main switch
on.
Select the data list mode on the hand–held tester.
2 Inspect combinatio ...
Inspection procedure
1 Check side air bag sensor assy lh
Sst 09843–18040
Connect the negative (–) terminal cable to the battery,
and wait at least for 2 seconds.
turn the ignition switch to on, and wait at least for 20 seconds.
clear the dtc stored in memory .
turn the ignition swi ...
Do-it-yourself service precautions
If you perform maintenance by yourself, be sure to follow the correct procedure
as given in these sections.
CAUTION
The engine compartment contains many mechanisms and fluids that may move suddenly,
become hot, or become electrically energized. To avoid death or serious injury,
observe t ...


