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:
Circuit description
Refer to dtcs p0100
Dtc no.
Dtc detection condition
Trouble area
P0101
After engine is warmed up, conditions (a) to (d) continue for
more than 10 seconds (2 trip detection logic):
engine speed less than 900 rpm
throttle valve fully closed
&nbs ...
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 ...
Inspection procedure
Hint:
troubleshoot each trouble symptom in accordance with the chart below.
1 Clear dtc
Connect the hand–held tester or the obd ii scan tool to the dlc 3.
turn the ignition switch on and push the hand–held tester or the
obd ii scan tool main switch on.
read the dtc . ...


