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 other dtc output(in addition p0121)
- 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 p0121 is output, perform the troubleshooting for those dtcs first.


Go to relevant dtc chart
Other materials:
Battery
Check the battery as follows.
■ Battery exterior
Make sure that the battery terminals are not corroded and that there are no
loose connections, cracks, or loose clamps.
1 Terminals
2 Hold-down clamp
■Before recharging
When recharging, the battery produces hydrogen gas which is ...
Precaution
Caution:
the corolla is equipped with srs, which comprises a driver airbag,
front passenger airbag
and side airbag. Failure to carry out service operations in the correct
sequence could cause
the srs to unexpectedly deploy during servicing, possibly leading to a
serious accident. Fu ...
Circuit description
In the diagram below, when the engine is cranked, current flows from terminal
st2 of the ignition switch to
the starter relay coil and also current flows to terminal sta of the ecm (sta
signal).
When the sta signal and ne signal are input to the ecm, tr is turned on, current
flows to the c ...


