User Manual
36
LAUNCH
Professional 909X User Manual
After reading the retrieved codes from the vehicle and certain repairs have been 
carried out, you can use this function to erase the codes from the vehicle. Before 
performing this function, please be sure the vehicle’s ignition key is in the ON 
position with the engine off.
Note: 
•  When this  function is  used  to erase  DTCs from  the vehicle’s on-board 
computer,  “Freeze  Frame” data  is erased  and  “Permanent” DTCs ARE 
NOT erased.
•  When  data  is  erased  from  the  vehicle’s  computer  memory,  the  I/M 
Readiness Monitor Status program resets  the  status  of all Monitors to a 
“Not Completed” status. To set all of the Monitors to a “Completed” status, 
an OBD II Drive Cycle must be performed. Refer to your vehicle’s service 
manual for information on how to perform an  OBD  II  Drive Cycle  for the 
vehicle under test.
After clearing, you should retrieve trouble codes once more or turn ignition on 
and retrieve codes  again. If there are  still some trouble codes  in the system, 
please troubleshoot the code using a factory diagnosis guide, then clear the 
code and recheck.
3. I/M Readiness
I/M refers to Inspection and Maintenance that is legislated by the Government 
to meet federal clean-air standards. I/M Readiness indicates whether or not the 
various emissions-related systems on the vehicle are operating properly and are 
ready for Inspection and Maintenance testing.
The purpose  of  the I/M  Readiness Monitor  Status  is to  indicate  which of  the 
vehicle’s Monitors have run and completed their diagnosis and testing, and 
which ones have not yet run and completed testing and diagnosis of their 
designated sections of the vehicle’s emissions system.
The I/M  Readiness Monitor  Status  function also  can be  used (after repair  of 
a fault has been performed) to confirm that the repair has been performed 
correctly, and/or to check for Monitor Run Status.










