Toyota Corolla (E120): Inspection procedure
Hint
: read freeze frame data using the hand-held tester or the obd ii scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air–fuel ratio was lean or rich, etc. At the time of the malfunction.
1 Check cooling system
- Check that there is a defect in the cooling system which causes overcool, such as abnormal radiator fan operation, modified cooling system and so on.


2 Inspect thermostat


3 Check other dtc output(in addition to dtc p0128)
- Connect the hand–held tester or the obd ii scan tool to the dlc3.
- turn the ignition switch on and push the hand–held tester or the obd ii scan tool main switch on.
- select the item ”diagnosis / enhanced obd ii / dtc info / current codes”.
- read the dtcs.
Result:

Hint
: if any other codes besides p0128 is output, perform the troubleshooting for those dtcs first.


Replace ecm
Other materials:
Diagnostic trouble code chart
If a dtc is displayed during the dtc check, check the circuit listed in the
table below and proceed to the
page given.
* :● ... Mil light up
...
Inspection procedure
Hint:
read freeze frame data using the hand-held tester or the obd ii scan tool.
Freeze frame data records the
engine conditions when a malfunction is detected. When troubleshooting, it is
useful for determining whether
the vehicle was running or stopped, the engine was warmed up or not, the ...
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 ...


