System Diagnosis

System diagnosis can be accomplished using an appropriate scan tool or an analog voltmeter. See RETRIEVING DTCS  . The TCL module monitors several different inputs. If an abnormal input signal occurs, a Diagnostic Trouble Code (DTC) is stored in TCL module memory and assigned a DTC number. Each circuit has its own DTC number and message. A specific DTC indicates a particular system failure, but does not indicate that cause of failure is necessarily within system.

A DTC does not condemn any specific component; it simply points out a probable malfunctioning area. If a DTC is set, the TCL module will turn on TCL warning light.