This procedure covers the following diagnostic code:
- 247-09 SAE J1939 Data Link abnormal update rate
The CAN data link is used to communicate information between the Electronic Control Module (ECM) and the Electronic Modular Control Panel (EMCP). Use this procedure to troubleshoot any suspect problems with the CAN data link.
This procedure identifies the following problems:
- Faulty connectors
- Missing termination resistors
- Short circuits
- Open circuits
- Faulty control module
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| Illustration 1 | g01421292 |
Test Step 1. Inspect the Electrical Connectors and the Wiring
- Turn the battery isolator switch to the OFF position.
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Illustration 2 g01186024 Location of the J1/P1 ECM connectors (typical left side engine view) - Thoroughly inspect the J1/P1 ECM connector. Inspect all of the connectors that are associated with the circuit. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect" for details.
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Illustration 3 g01240928 P1 terminals that are associated with the CAN data link
(P1-34) CAN data link −
(P1-50) CAN data link +Show/hide table
Illustration 4 g01421364 Terminals at the service tool connector that are associated with the CAN data link
(G) CAN data link +
(F) CAN data link − - Perform a
45 N (10 lb) pull test on each of the wires that are associated with the CAN data link. - Check the allen head screw on each ECM connector for the proper torque. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
- Check the allen head screw on the customer connector for the proper torque. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect" for the correct torque value.
- Check the wiring harnesses for abrasion, for corrosion and for pinch points.
Expected Result:
All connectors, pins and sockets are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion and of pinch points.
Results:
- OK - The harness and the wiring appear to be OK. Proceed to Test Step 2.
- Not OK - There is a problem in the wiring harness.
Repair: Repair the connectors and/or the wiring. Replace parts, if necessary. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled. Verify that the problem is resolved.
STOP
Test Step 2. Verify the Proper Installation of the CAN Data Link
- Disconnect the EMCP.
- Disconnect the P1 connector and measure the resistance between terminals P1-50 (CAN data link +) and P1-34 (CAN data link -).
Expected Result:
The resistance is between 57 and 63 Ohms.
Results:
- OK - The resistance is between 57 and 63 Ohms. Proceed to Test Step 5.
- Not OK - The resistance is between 114 Ohms and 126 Ohms. A terminating resistor is missing.
Repair: Verify that two terminating resistors exist on the data link. One resistor must be located on each end of the data link. The engine is shipped with one terminating resistor that is installed between the ECM and the customer connector.
Refer to the appropriate electrical schematic in order to determine the missing resistor. Replace the missing resistor. Verify that the problem is resolved.
STOP
- Not OK - The resistance is less than 57 Ohms. Proceed to Test Step 3.
- Not OK - The resistance is greater than 126 Ohms. Proceed to Test Step 4.
Test Step 3. Check for a Short Circuit
- Disconnect the J1/P1 ECM connector.
- Remove the terminating resistors from the CAN data link.
- Disconnect the EMCP.
- Measure the resistance between the points that are listed in Table 1. Be sure to wiggle the wires in the harnesses as you make each resistance measurement.
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Table 1 Resistance Measurements for the CAN Data Link Connector and Terminal Terminal P1-50 (CAN data link +) All of the other terminals on the P1 connector Engine ground P1-34 (CAN data link -) All of the other terminals on the P1 connector Engine ground
Expected Result:
Each check of the resistance indicates an open circuit.
Results:
- OK - Each check of the resistance indicates an open circuit. Proceed to Test Step 4.
- Not OK - At least one check of the resistance does not indicate an open circuit. There is a short circuit in a harness. There may be a problem with a connector.
Repair: Repair the wiring and/or the connector. Replace part, if necessary. Verify that the problem is resolved.
STOP
Test Step 4. Check for an Open Circuit
- Verify that all of the connections are disconnected.
- Fabricate a jumper wire. Use the jumper wire in order to create a short circuit between terminals G and F on the service tool connector.
- Measure the resistance between terminals P1-50 (CAN data link +) and P1-34 (CAN data link -).
- Remove the jumper wire from the service tool connector.
Expected Result:
The resistance is less than ten Ohms.
Results:
- OK - The resistance is less than ten Ohms. There is not an open circuit. Proceed to Test Step 5.
- Not OK - The resistance is more than ten Ohms. There is an open circuit or excessive resistance in the circuit. There may be a problem in a connector.
Repair: Repair the wiring and/or the connector. Replace part, if necessary. Verify that the problem is resolved.
STOP
Test Step 5. Check the EMCP
- Connect the EMCP to another engine.
- Operate the engine and monitor the EMCP.
Expected Result:
The EMCP operates properly.
Results:
- OK - The EMCP operates properly on another engine.
Repair: Connect the display to the original engine. If the display operates correctly, there may be a problem with an electrical connector. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".
If the display does not operate correctly on the original engine, there may be a problem with the ECM.
It is unlikely that the ECM has failed. Perform this entire procedure again. Replace the ECM if the display does not operate correctly. Refer to electronic troubleshooting Troubleshooting, "Replacing the ECM".
STOP
- Not OK - The EMCP does not operate properly on another engine.
Repair: Replace the EMCP. Verify that the problem is resolved.
STOP