Dual Electronic Automatic Temperature Control (DATC) Module Diagnostic Trouble Codes — DTCs If using the scan tool or front panel diagnostics to check for DATC DTCs: 1. Check continuous DTCs. 2. Run DATC self-test. Refer to Front Panel DATC Self-Test (On-demand Diagnostic Trouble Codes — DTCs). General Information: If the DTC is continuous only and does not appear in the self-test, this indicates an intermittent fault condition, such as a poor wiring connection or a loose terminal. If the DATC does not appear after running the self-test it may also indicate that the DTC may no longer exist. If the DTC is continuous and appears in the self-test, this indicates a hard fault. A hard fault suggests a permanent wiring failure, disconnected connector or component failure. Front Panel DATC Module Self-Test (On-Demand Diagnostic Trouble Codes — DTCs) On-demand DTCs are those that are reported by an ECU when a failure is detected while executing a diagnostic test. For the DATC module this means that all faults (hard) that occur while the module is conducting a self-test shall be reported as an on-demand DTC. The DATC module self-test will not detect concerns associated with data link messages such as engine coolant temperature or vehicle speed signals. The scan tool must be used to retrieve these concerns. The vehicle interior temperature should be between 0-32°C (32-90°F) when carrying out the self-test. I f the temperatures are not within the specified ranges, false temperature sensor DTCs may be displayed. The DATC module self-test through the front panel display: can be initiated at any time. Normal operation of the system stops when the self-test is activated. is entered by pressing the OFF and DEFROST buttons simultaneously and then pressing the AUTO button within two seconds. Record all DTCs displayed. concludes by reporting all on-demand DTCs. Follow the diagnostics procedure given under ACTION in the DTC index for each DTC given. reports individual on-demand DTCs as four-digit DTCs (less the alpha character). will calibrate all the mode doors and check all analog inputs. The DATC module will only report on-demand (hard) faults that occurred while the DATC module was conducting its self- test. will light all control panel display segments if no faults are detected. will report individual on-demand DTCs without the °C symbol lit.