Toyota Corolla Repair Manual: 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

1. 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)

1. Connect the hand–held tester or the obd ii scan tool to the dlc3.
2.  turn the ignition switch on and push the hand–held tester or the obd ii scan tool main switch on.
3.  select the item ”diagnosis / enhanced obd ii / dtc info / current codes”.
4.  read the dtcs.

Result:

Hint

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

Replace ecm