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:
Engine assembly
Inspection
1. Inspect coolant
2. Inspect engine oil
3. Inspect battery
4. Inspect air cleaner filter element sub–assy
5. Inspect spark plug
6. Inspect fan and generator v belt
Hint:
you don’t need to check the belt deflection because auto tensioner is adopted.
7. Inspect ignition ti ...
Definition of terms
Term
Definition
Monitor description
Description of what the ecm monitors and how it detects malfunction
(monitoring purpose and its details).
Related dtcs
Diagnostic code
Typical enabling condition
Preconditions that allow the ecm to detect m ...
Circuit description
The variable valve timing (vvt) system includes the ecm, the oil control
valve (ocv) and the vvt controller.
The ecm sends a target ”duty–cycle” control signal to the ocv. This control
signal, applied to the ocv,
regulates the oil pressure supplied to the vvt controller. Camshaft timin ...


