HEAD 4914780 - Caterpillar

Illustration 6 g01355248
Terminal locations at the termination resistors
(A) CAN data link +
(B) CAN data link −
(C) Shield
Table 2
Troubleshooting Test Steps Values Results
1. Inspect the Electrical Connectors and the Wiring
Note: Carefully follow this procedure to identify an intermittent problem.
A. Perform a visual inspection of the wiring between the P1 and P2 ECM connectors, the termination resistors, and the service tool connector. Also, inspect the wiring and the connectors at various controllers and control boxes.
Look for these problems:
-Harness damage that is caused by chafing
- Harness damage that is caused by excessive heat
-Look for moisture on the wiring and in the connectors.
- Pull on the wires that are associated with the data links.
This test verifies that the wire is properly crimped to the terminal and that the terminal is properly inserted into the connector.
Connectors
Result: The wiring and the connectors appear to be OK.
Proceed to Test Step 2.
Result: There is a problem with the wiring or with a connector.
Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all the connector seals are properly in place and ensure that the connectors are coupled.
Verify that the repair eliminates the problem.
2. Bypass the Wiring for the Data Link
A. Connect the 217-0113 Wiring Harness (ECM BYPASS) to the J1 connector, to the 332-7381 Data Link Cable As, and to the battery.
B. Restore the electrical power to the ECM.
C. Try to establish communication between Cat ET and the ECM.
Data link
Result: Cat ET and the ECM communicate.
Repair: Cat ET and the ECM communicate when the bypass harness is installed. However, communication cannot be established via the engine wiring.
Disconnect the electrical connector from each of the control modules that is on the data link one at a time. This test will isolate the problem. Try to establish communication between Cat ET and the ECM after disconnecting each module.
The problem is in the control module if disconnecting the module allows Cat ET and the ECM to communicate. If a module is suspect, replace the module.
Verify that the repair eliminates the problem.
The control module is OK if the problem remains when the module is disconnected.
Result: Cat ET and the ECM do not communicate.
Repair: Communication between Cat ET and the ECM is not established when the bypass harness is installed. Temporarily connect a test ECM. Refer to Troubleshooting, "Test ECM Mode".
Note: Before you consider replacing the ECM, consult with the Dealer Solutions Network (DSN) for assistance.
Verify that the repair eliminates the problem.
3. Check the Wiring for the Data Links for a Short Circuit
A. Turn the main disconnect switch to the OFF position.
B. Disconnect the negative cable from the battery.
C. Disconnect the P1 and P2 ECM connectors from the ECM.
D. Measure