3516B and 3516C Engines For MT4400D AC Off-Highway Trucks Caterpillar

Data Link - Test

Usage:

Use this procedure to troubleshoot the data link if a problem is suspected with the data link.

Use this procedure to troubleshoot the electrical system if a problem is suspected with the CAN data link or the Cat Data Link.

Note: This procedure checks for an open or for a short in the data link circuits.

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Table 1
Diagnostic Codes
Code and Code Description	Conditions which Generate this Code	System Response
246-9 Proprietary CAN Data Link : Abnormal Update Rate	All communications on the data link have been lost.	The code is logged.
246-14 Proprietary CAN Data Link : Special Instruction	Partial communications on the data link have been lost.	The code is logged.
247-9 SAE J1939 Data Link : Abnormal Update Rate	All communications on the data link have been lost.	The code is logged.
247-14 SAE J1939 Data Link : Special Instruction	Partial communications on the data link have been lost.	The code is logged.
248-9 Cat Data Link not communicating	All communications on the data link have been lost.	The code is logged.
248-14 CAT Data Link : Special Instruction	Partial communications on the data link have been lost.	The code is logged.
625-14 Proprietary Data Link : Special Instruction	Partial communications on the data link have been lost.	The code is logged.
639-9 J1939 Network #1 : Abnormal Update Rate	All communications on the data link have been lost.	The code is logged.
639-14 J1939 Network #1 : Special Instruction	Partial communications on the data link have been lost.	The code is logged.
3050-9 Drivetrain Control : Abnormal Update Rate	All communications on the data link have been lost.	The code is logged.
3050-14 Drivetrain Control : Special Instruction	The ECM has lost partial communications to the transmission control module over the Cat Data Link.	The code is logged.

If Cat^® Electronic Technician (Cat^® ET) will not communicate with the ECM, refer to Troubleshooting, "Electronic Service Tool Does Not Communicate" before you begin this procedure. The procedure will verify that electrical power is being supplied to the ECM and to the service tool connector.

The data links are used to communicate information between the engine ECM and other control modules that are a part of the application. Cat ET also communicates with the ECM via the data links.

The service tool connector contains connections for electrical power and for the data links.

When the keyswitch is in the OFF position, Cat ET may communicate with the ECM. However, the communications may be disrupted and the communications may require frequent reconnection. In order to avoid this problem, place the keyswitch in the ON position when Cat ET is being used.

Cat ET may display the following error message:

"The version of the ECM is not recognized and the integrity of the changed parameters and displayed data is not guaranteed."

This message indicates one of the following conditions:

The flash file in the ECM is newer than the version of Cat ET.
The latest version of Cat ET has not been installed.

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Illustration 1	g03368559
Typical data link schematic

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Illustration 2	g01444702
Terminal locations at the service tool connector (A) +Battery (B) -Battery (C) CAN data link global shield (D) Cat Data Link + (E) Cat Data Link - (F) CAN data link global - (G) CAN data link global +

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Illustration 3	g01559974
Terminal locations at the P1 ECM connector that are for the data links (P1-8) Cat Data Link + (P1-9) Cat Data Link - (P1-34) Global CAN data link - (P1-42) Global CAN shield (P1-48) +Battery (P1-50) Global CAN data link + (P1-52) +Battery (P1-53) +Battery (P1-55) +Battery (P1-57) +Battery (P1-61) -Battery (P1-63) -Battery (P1-65) -Battery (P1-67) -Battery (P1-69) -Battery (P1-70) Keyswitch

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Illustration 4	g01355248
Terminal locations at the termination resistors (A) CAN data link + (B) CAN data link - (C) Shield

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Illustration 5	g03153416
Terminal locations at the engine interface connector (Terminal 5) Cat Data Link + (Terminal 6) Cat Data Link - (Terminal 28) Global CAN data link shield (Terminal 33) Global CAN data link + (Terminal 34) Global CAN data link -

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Table 2
Troubleshooting Test Steps	Values	Results
1. Inspect the Electrical Connectors and the Wiring Note: Carefully follow this procedure in order 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	Results: The wiring and the connectors appear to be OK. Proceed to Test Step 2 Results: There is a problem with the wiring or with a connector. Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of 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	Results: 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. Results: 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 ECM connector from the ECM. D. Measure the resistance between the following terminals at the ECM: -P1-8 (Cat Data Link +) and P1-61 (-Battery) -P1-9 (Cat Data Link -) and P1-61 (-Battery) -P1-34 (Global CAN data link -) and P1-61 (-Battery) -P1-50 (Global CAN data link +) and P1-61 (-Battery)	Short Circuit	Results: Each measurement indicates an open circuit. The wiring for the data links does not have a short circuit. Proceed to Test Step 4. Results: At least one measurement does not indicate an open circuit. Repair: At least one measurement is less than five Ohms. The wiring for a data link has a short circuit. Determine the cause of the short circuit. Repair the problem, when possible. Replace parts, if necessary. Verify that the repair eliminates the problem.
4. Check the Wiring for the Data Links for an Open Circuit A. Connect a jumper wire between terminals P1-8 and P1-9 at the primary ECM. B. At the service tool connector and the connector for each control module, measure the resistance between the terminals for the Cat Data Link. C. Connect a jumper wire between terminals P1-34 and P1-50 D. At each service tool connector measure the resistance between the terminals for the CAN data link. Also, at the connector for each control module on the global network, measure the resistance between the terminals for the CAN data link. F. At each service tool connector measure the resistance between the terminals for the CAN data link. Also, at the connector for each control module on the global network, measure the resistance between the terminals for the CAN data link.	Open circuit	Results: All of the resistance measurements indicate a short circuit. Repair: If you are troubleshooting the Cat Data Link, the data link appears to be OK. The problem is probably an intermittent problem in a connector or in the harness. If the problem persists, perform this test procedure again. If an intermittent problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect" for information that is related to troubleshooting intermittent electrical problems. If you are troubleshooting the CAN data link, remove the jumper wires. Leave the control modules disconnected from the data link Proceed to Test Step 5 Results: At least one of the resistance measurements indicates an open circuit. Repair: Determine the cause of the open circuit. Repair the problem, when possible. Replace parts, if necessary. Verify that the repair eliminates the problem.
5. Check the Termination Resistors for the J1939 Data Link Perform this test step only if you are troubleshooting a problem with the CAN data link. A. Ensure that all of the control modules are disconnected from the data link. At the service tool connector, measure the resistance between the terminals for the CAN data link.	45 Ohms and 75 Ohms	Results: The resistance is between 45 Ohms and 75 Ohms. Repair: The termination resistors are OK. The data link appears to be OK. The problem is probably an intermittent problem in a connector or in the harness. If the problem persists, perform this test procedure again. If an intermittent problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect" for information that is related to troubleshooting intermittent electrical problems Results: The resistance is approximately 120 Ohms. There is a problem with a termination resistor. Repair: Determine the cause of the missing termination resistor. Repair the problem, when possible. Replace parts, if necessary. Verify that the problem is resolved. Results: The resistance is greater than 140 ohms. There is a problem with both termination resistors. Repair: Determine the cause of the problem. Repair the problem, when possible. Replace parts, if necessary. Verify that the repair eliminates the problem.

If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).