Purpose of the Readiness Tests: Notes

The On-Board Diagnostic (OBD II) system is designed to monitor the performance of emission-related components and report any detected abnormalities in the form of Diagnostic Trouble Codes (DTCs). Since the various components need to be monitored during different driving conditions, the OBD II system is designed to run separate monitoring programs called Readiness Monitors. Many state emissions inspection and maintenance (I/M) programs require that vehicles complete their Readiness Monitors prior to beginning an emissions test.

NOTE: A diagnostic trouble code for a subsystem or component within a subsystem will not set until the associated readiness monitor is complete.

The readiness monitor status will be reset to incomplete if:

The battery is disconnected.
DTCs have been cleared.
The monitor drive cycle has not been completed.

The monitor status can be checked using an OBD II scan tool. When using hand-held tester, monitor status can be found in the Enhanced OBD II Extended Data List or under CARB OBD II. In the event that any monitors show incomplete, follow the appropriate Readiness Monitor Drive Pattern to change the readiness status to "complete".

Identifying Drive Patterns

Pattern No.	Readiness Code Patterns
1	EGR Monitor (Except 1FZ-FE engine)
2	EGR Monitor (For 1FZ-FE engine)
3	Catalyst Monitor (Front and rear heated oxygen sensors equipped)
4	Catalyst Monitor (A/F sensor equipped)
5	EVAP Monitor (Fuel tank pressure monitor)
6	EVAP Monitor (Vacuum monitor and LEV II)
7	EVAP Monitor (Engine RPM monitor)
8	Heated Oxygen Sensor Monitor (Front and rear heated oxygen sensors equipped)
9	A/F Sensor and Heated Oxygen Sensor Monitor (Front A/F sensor and rear heated oxygen sensor equipped)
10	Oxygen Sensor Heater and A/F Sensor Heater Monitor

CAUTION: Strict observance of posted speed limits, traffic laws, and road conditions are required when performing these drive patterns.

NOTE: These drive patterns represent the fastest method to satisfy all necessary conditions which allow the specific readiness monitor to complete.
In the event that the drive pattern must be interrupted (possibly due to traffic conditions or other factors) the drive pattern can be resumed and, in most cases, the readiness monitor will still set to complete.
To ensure rapid completion of readiness monitors, avoid sudden changes in vehicle load and speed (driving up and down hills and/or sudden acceleration).

Available Model for Readiness Code Set Drive Pattern (TOYOTA Models):

Fig 1: 1996 Toyota Models