AL529 User Manual V1.00

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Figure 4-26 Sample I/M Readiness Screen
The green, yellow and red LEDs provide a quick way to help you determine
if a vehicle is ready for an Emission Test.
OK – indicates that a particular monitor being checked has completed
its diagnostic testing.
INC – indicates that a particular monitor being checked has not
completed its diagnostic testing.
N/A – the monitor is not supported on the vehicle.
The LED and audio tone are interpreted as below:
LED Interpretation
 GREEN LED – indicates that engine systems are “OK” and operating
normally (the number of Monitors supported by the vehicle that have
run and performed their self-diagnostic testing is in the allowed limit.
MIL is off).There are neither stored nor pending DTCs. The vehicle is
ready for an Emissions Test, and there is a good possibility that it can
be certified.
 YELLOW LED – with MIL off, there may be three possible conditions to
cause the yellow LED to light.
 If a “Stored” Diagnostic Trouble Code is causing the Yellow LED to
light, it is still possible that the vehicle will be allowed to be tested
for emissions and certified.
 If a “Pending” Diagnostic Trouble Code is causing the Yellow LED
to light, it is still possible that the vehicle will be allowed to be tested
for emissions and certified.