Applicable Systems
EMCP 4.2
Symptoms
CID 489 (CAN Bus Off): Condition exists. The Caterpillar Electronic Technician (Cat ET) displays this fault. Machine operation may be derated or shut down depending on severity.
Possible Causes
- Sensor or actuator for CAN Bus Off failed or out of range
- Wiring harness for CID 489 circuit open, shorted, or corroded
- ECM parameter for CAN Bus Off out of calibration
- Mechanical or hydraulic issue affecting the component
Troubleshooting Steps
- Step 1: Connect Cat ET and read active fault codes for CID 489
Fault code 489-31 displayed with timestamp and component data - Step 2: Inspect wiring harness and connector for CID 489 (CAN Bus Off)
Wiring intact, connector clean and seated - Step 3: Test CAN Bus Off sensor or actuator output
Output within Caterpillar specification range - Step 4: Check ECM for stored parameters and calibrate if needed
Parameters within factory specification - Step 5: Clear fault with Cat ET and verify no re-occurrence
Fault cleared and does not return after test cycle
How to Reset
To reset: 1) Correct the underlying fault for CID 489. 2) Press FAULT RESET on the EMCP panel or clear via Cat ET. 3) Verify machine returns to normal operation. Caution: Do not reset without repairing the fault as the machine may operate in derated mode.
Frequently Asked Questions
- Q: What does CID 489 mean on Caterpillar equipment?
CID 489 refers to CAN Bus Off. It is a standard Caterpillar Component Identifier used in diagnostic systems.
- Q: What does FMI 31 mean?
FMI 31 indicates: Condition exists. FMI (Failure Mode Identifier) describes the type of failure detected.
Comments (0)
Share your experience to help others facing the same problem.
Leave a Comment
Source: Caterpillar SAE J1939 CID/FMI Reference, wholefleet.ca/motorsymphdiesel.com
Category: Generator
No comments yet. Be the first to share your experience!