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:
Removal & installation and disassembly & reassembly
1. Remove bench type rear seat cushion assy
2. Remove rear floor service hole cover
Remove the rear service hole cover.
Disconnect the fuel pump and vapor pressure sensor
connector.
3. Work for preventing gasoline from spilling out
Start the engine.
after the engi ...
Confirmation driving pattern
Connect the hand–held tester or the obd ii scan tool to the dlc3.
record dtcs and the freeze frame data.
set the check mode using the hand–held tester .
read the value on the misfire counter for each cylinder when
idling. If the value is displayed on the
misfire c ...
Inspection procedure
Hint:
when the throttle position is slightly opened (the accelerator pedal
is slightly depressed) because a
floor carpet is overlapped on the accelerator pedal, or if not fully
releasing the accelerator pedal, etc.,
Dtc p505 will possibly be detected.
Read freeze frame data using the ...


