Trip Computer: Testing and Inspection
COMPASS MINI-TRIP COMPUTERCompass Mini-Trip Computer (CMTC) data is obtained from other electronic modules (CCN, FCM and JTEC) on the J1850 Data Bus circuit. The CMTC will display dashes (- -) for any of the screens it did not receive the bus messages. The label corresponding to the missing information will be lit. If no compass mini-trip computer data is displayed, check the J1850 Data Bus circuit communications and the other modules. If the brightness level is improper check the J1850 Data Bus circuit.
Refer to Overhead Console Diagnosis and Testing for instructions on performing a CMTC module Self-Diagnostic Test. The DRB III is recommended for checking the J1850 Data Bus circuit and the other modules. Perform the CMTC self diagnosis before replacing the CMTC module.