DTC (Diagnostic Trouble Codes)
Table 3:
The Instrument Panel Cluster may, under certain circumstances, set it's own Diagnostic Trouble Codes (DTCs) over the UART Data Line. These can be found by using the "DTC" mode of the TECH 2. The first instance a DTC could be set is for Vehicle Theft Deterrent operation.
The second instance is when there is a loss of serial data with one or more of the Modules on the UART Data Line. Such a loss could be the result of an open or short in the UART Data Line or CKT 800. These codes can be especially useful when diagnosing an intermittent problem. An explanation of these are given below in TABLE #3.