No COMM From Micro to Display
system
Description
The main microprocessor cannot communicate with the display module over the CAN bus, and the unit gives alarm only while continuing to run.
Activation Conditions
If alarm 21100 No COMM From Any Board to Main Micro is not active and main microprocessor cannot communicate with the display module over the CAN bus.
Unit Behavior
Alarm only, unit will continue to run. Module may display “LOSS OF COMMUNICA- TIONS”.
Reset Conditions
Auto reset when CAN communication is restored, or alarm may be manually reset by turning the unit off, then back on again.
Corrective Actions
Check CAN bus a. Inspect connector pins and terminals on 1MM, 1SVM, DM and ENCU. Verify no damage or corrosion in connections. b. Check display LOSS OF COMMUNICATIONS message is displayed. c. Check for CAN circuit continuity: CAN Hi; Check entire circuit, 1MM-2 to DM-2. If circuit is open, check individual paths as follows: 1MM-2 through SP-1 to 1SVM-5 and ENCU-23 and 1SVM-2 and DM-2 CAN Lo; Check entire circuit, 1MM-4 to DM-6. If circuit is open, check individual paths as follows:1MM-4 through SP-4, to 1SVM-7 and ENCU-24, and 1SVM-4 and DM-6 d. Check for good continuity. If not, check connectors and wiring between terminals. Verify no damage, moisture or corrosion.