Each version KE has different meanings attached to the Duty-cycle IR values coming from the left side diagnostic port. Your year should give 70% key on engine off. If its a Ca version it should be 85%.
While running a fixed duty cycle indicates a code/fault. A 40% fixed duty-cycle would indicate a problem with the airflow sensor position indicator (B2). While running in closed loop the duty cycle will vary up and down as the mixture is corrected rich-lean. A properly adjusted car will have the oscillating duty cycle hovering around 50%. I usually bias my settings rich by setting mixture to a hover over 40%. It must be moving though to get a value otherwise a code is being set.