Diagnostic Trouble Codes (DTCS)
WARNING: This page is about a different car, the 2010 Volvo V70, 2009 Volvo V70, and 2008 Volvo V70. However, it is still accessible from the selected car via links, so may be relevant.
Diagnostic trouble codes (DTCs) are stored in the control module if the climate control module (CCM) detects a fault. Each diagnostic trouble code (DTC) has a counter which records the number of operating cycles which have been fault-free since the diagnostic trouble code (DTC) was last stored. A fault which is detected in the present operating cycle is defined as permanent. A fault which is detected in one or more operating cycles (although not the present one) is defined as intermittent.
An operating cycle is the period from when the ignition has been off, then on for at least 10 seconds and finally off for at least 10 seconds.