DIAGNOSTICS on 2001 Volvo S60

HI THERE WHEN I PLUG IN MY

U480 OBD2 Car Diagnostic Fault Code Reader Scanner IT SCANS AND SAYS NO CODES IS THIS GOOD OR BAD BUT THE PROBLEM IS I HAVE AN ERRATIC IDLE WHICH IS MOST DEFINATELY THE ETM SO WHY WONT IT SHOW A CODE FOR THAT ANY HELP PLEASE THANKS

Asked by for the 2001 Volvo S60
1 answer 1 comment
There are many possibilities for this. I'm not familiar with that scan tool, but it may not be able to read all the codes, which is common for simple OBD scanners. You may also have a dirty ETM, which wont set a code.
Is the Check Engine Light on?
no the check engine light is not on the diagnostics show no error codes thanks