Toyota Corolla (E120): Fail–safe chart
If any of the following codes is recorded, the ecm enters the fail–safe mode.

Check for intermittent problems
Hand–held tester only:
by putting the vehicle’s ecm in the check mode, the 1 trip detection logic is possible instead of the 2 trip detection logic, and the sensitivity to detect faults is increased. This makes it easier to detect intermittent problems.
- Clear the dtcs .
- set the check mode .
- perform a simulation test .
- check the connector and terminal .
- wiggle the harness and connector
Other materials:
Check mode procedure
Hint:
hand–held tester only:
compared to the normal mode, the check mode has more sensing
ability to detect malfunctions. Furthermore, the same diagnostic
items which are detected in the normal mode can also be
detected in the check mode.
1. Check mode procedure(using the hand–held tester) ...
Inspection procedure
1 Check security indicator light
Remove the security indicator.
check the indicator light, as shown in the illustration and
table.
Standard:
2 Check wire harness (tvip ecu security indicator)
Disconnect the tvip ecu and security indicator connectors.
  ...
Circuit description
The ignition switch provides circuit power and the ecm provides the circuit
ground that illuminates the mil.
Mil operation is checked visually:
it should be illuminated when the ignition is first turned on. If the mil is off
all of the time or on all of the time,
use the procedure below to ...


