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Stored Codes
Stored codes are emissions-related DTCs from the ECU of the vehicle. OBDII/EOBD
codes are prioritized according to their emissions severity, with higher-priority codes
overwriting lower-priority ones. The priority of the code determines the illumination
of the Malfunction Indicator Light (MIL) and the codes erase procedure.
Manufacturers rank codes differently, so DTCs may vary by vehicle.
Pending Codes
These are codes whose storing conditions have been met during the last drive cycle,
but need to be met on two or more consecutive drive cycles before the DTC is stored.
The purpose of displaying pending codes is to assist the service technician after a
vehicle repair when diagnostic information is cleared, by reporting test results after
a single drive cycle.
a) If a test fails during the drive cycle, the DTC associated will be reported. If the
pending fault does not occur again within 40 to 80 warm-up cycles, the fault is
automatically cleared from memory.
b) Test results reported do not necessarily indicate a faulty component or system.
If test results indicate another failure after additional driving, a DTC is stored to
indicate a faulty component or system.
Freeze Frame
In most cases, the stored frame is the last DTC reported. Certain DTCs, those that
have a greater impact on vehicle emission, have a higher priority. In these cases,
DTCs of the highest priority will be retained. Freeze frame data includes a "snapshot"
of critical parameter values at the time the DTC is stored.
Erase Codes
This option is used to clear all emissions-related diagnostics data including DTCs,
freeze frame data, and specific manufacturer-enhanced data from the vehicle ECU.
This option resets the I/M Readiness Monitor Status for all vehicle monitors to
“Not
Ready
” or “Not Complete”.
A confirmation screen will appear when the Clear Codes option is selected to prevent
accidental loss of data. Select
Yes
on the confirmation screen 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 local emissions compliance.
Selecting I/M Readiness opens a submenu with two choices:
Since DTCs Cleared
— displays the status of monitors since the last time the DTCs
were erased.
This Drive Cycle
— displays the status of monitors since the beginning of the current
drive cycle.
