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 fuel receiver gauge
Wiring diagram
Inspection procedere
1 Inspect fuel sender gage assy
Disconnect the connector fuel sender gauge.
check the float position between e and f and measure
the resistance between terminals 2 and 3 of the connector.
Check that the resistance value changes continuously.
S ...
Emission inspection and maintenance (I/M) programs
Some states have vehicle emission inspection programs which include OBD (On
Board Diagnostics) checks. The OBD system monitors the operation of the emission
control system.
If the malfunction indicator lamp comes on
The OBD system determines that a problem exists somewhere in the emission cont ...
Oxygen sensor monitor (front and rear o2s system)
Preconditions
The monitor will not run unless:
mil is off
drive pattern
connect the obd ii scan tool to the dlc3 to check monitor status
and preconditions.
Start the engine and allow it to idle for 2 minutes or more.
Drive the vehicle at 25 mph ...


