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cases, the top prioritized DTC is the one for which the freeze frame records
are retained. Freeze frame data includes a “snapshot” of critical parameter
values at the time the DTC is set.
Erase Codes
This option is used to clear all emission-related diagnostic data such as,
DTCs, freeze frame data and manufacturer-specific enhanced data from
the vehicle’s ECM, and reset the I/M Readiness Monitor Status for all
vehicle’s ECM.
A confirmation screen displays when the clear codes option is selected to
prevent accidental loss of data. Select Yes to continue or No to exit.
I/M Readiness
This function is used to check the readiness of the monitoring system. It is an
excellent function to use prior to having a vehicle inspected for state emissions
compliance. Select I/M Readiness to display a sub menu with two choices:
Since DTCs Cleared – displays the status of monitors since the last time
the DTCs are erased.
This Driving Cycle – displays the status of monitors since the beginning
of the current drive cycle.
Live Data
This function displays the real time PID data from ECU. Displayed data
includes analog inputs and outputs, digital inputs and outputs, and system
status information broadcast on the vehicle data stream.
Live data can be displayed in various modes, see Live Data on page 32 for
detailed information.
O2 Sensor Monitor
This option allows retrieval and viewing of O2 sensor monitor test results for
the most recently performed tests from the vehicle’s on-board computer.
The O2 Sensor Monitor test function is not supported by vehicles which
communicate using a controller area network (CAN). For O2 Sensor Monitor
tests results of CAN-equipped vehicles, refer to On-Board Monitor.
