C11, C13, C15, and C18 Industrial Engines Caterpillar

Use this procedure to troubleshoot the electrical system if a problem is suspected with the CAN data link or the Cat Data Link. Also use this procedure if a diagnostic code in Table 1 is active or easily repeated.

Table 1

Diagnostic Codes Table
CDL Code and Description	Comments
246-9 Proprietary CAN Data Link : Abnormal Update Rate	The Electronic Control Module (ECM) has lost communications over the CAN data link. The code is logged. The check engine lamp is illuminated.
247-9 SAE J1939 Data Link : Abnormal Update Rate	The ECM has lost all communications over the global CAN data link. The code is logged. The check engine lamp is illuminated.
296-9 Transmission Control : Abnormal Update Rate	The ECM has lost all communications with the transmission over the Cat Data Link. The code is logged. The check engine lamp is illuminated.
297-9 All Wheel Drive Control : Abnormal Update Rate	The ECM has lost all communications with the all wheel drive over the Cat Data Link. The code is logged. The check engine lamp is illuminated.
562-9 Caterpillar Monitoring System : Abnormal Update Rate	The ECM has lost all communications with the Cat Monitoring System over the Cat Data Link. The code is logged. The check engine lamp is illuminated.
596-9 Implement Control : Abnormal Update Rate	The ECM has lost all communications with the implement control over the Cat Data Link. The code is logged. The check engine lamp is illuminated.
639-9 J1939 Network #1 : Abnormal Update Rate	The Electronic Control Module (ECM) has lost communications over the J1939 data link. The code is logged. The check engine lamp is illuminated.
1603-9 Machine Control Module : Abnormal Update Rate	The code is logged. The check engine lamp is illuminated.
1639-2 Machine Security System Module : Erratic, Intermittent, or Incorrect	The ECM has lost communications with the Machine Security System Module (MSSM) over the Cat Data Link. The code is logged. The check engine lamp is illuminated.
1639-9 Machine Security System Module : Abnormal Update Rate	The ECM has lost all communications with the Cat Monitoring System over the Cat Data Link. The code is logged. The check engine lamp is illuminated.
3397-9 DPF #1 Soot Loading Sensor : Abnormal Update Rate	The ECM has lost all communications with the DPF #1 Soot Loading Sensor over the Cat Data Link. The code is logged. The check engine lamp is illuminated.
3472-9 ARD Air Pressure Control System : Abnormal Update Rate	The ECM has lost all communications with the ARD combustion air controller over the Cat Data Link. The code is logged. The check engine lamp is illuminated.

Note: If a 1639-2 diagnostic code is active, verify that the following information is correct before proceeding with this procedure:

• The part number of the flash software for the Machine ECM

• The part number of the flash software for the Machine Security System ECM

• The part number of the Machine ECM

• The part number of the Machine Security System ECM

Illustration 1	g02112358
Schematic for the Cat Data Link and the CAN data link

Probable Causes

• Short circuit

• Open circuit

• Termination resistors

Recommended Actions

Table 2

Troubleshooting Test Steps	Values	Results
1. Check for a Short Circuit A. Turn the keyswitch to OFF. B. Thoroughly inspect the connectors that are associated with the data link circuits. Refer to Troubleshooting, "Electrical Connectors - Inspect". C. Disconnect the P1 and the P2 ECM connector. D. Disconnect Cat ET from the service tool connector. E. Measure the resistance between the points that are listed below. Be sure to wiggle the wires in the harnesses as you make each resistance measurement. - P1-8 to all P1 connector terminals and negative ground - P1-9 to all P1 connector terminals and negative ground - P1-50 to all P1 connector terminals and negative ground - P1-34 to all P1 connector terminals and negative ground - P2-12 to all P2 connector terminals and negative ground - P2-11 to all P2 connector terminals and negative ground	Short circuit	Result: Each check of the resistance indicates an open circuit. Proceed to Test Step 2 Result: At least one check of the resistance does not indicate an open circuit. There is a short circuit in the harness or in a connector. Repair: Repair the connectors and/or the wiring. Replace parts, if necessary. Verify that the original problem is resolved.
2. Check for an Open Circuit A. Fabricate a jumper wire that is long enough to create a test circuit across two terminals. Create a short circuit between terminals D and E on the service tool connector. B. Measure the resistance between P1-8 and P1-9. C. Fabricate a jumper wire that is long enough to create a test circuit across two terminals. Create a short circuit between terminals G and F on the service tool connector. D. Measure the resistance between P1-50 and P1-34). E. Fabricate a jumper wire that is long enough to create a test circuit across two terminals. Use the jumper wire to create a short circuit between terminals 23 and 24 on the Clean Emissions Module (CEM) connector. F. Measure the resistance between P2-12 and P2-11.	Open circuit	Result: Each check of the resistance indicates a short circuit. Remove the jumper wire from the service tool connector. Proceed to Test Step 3. Result: At least one of the resistance measurements indicates an open circuit. Repair: Remove the jumper wire from the ECM connector. Determine the cause of the open circuit. Repair the problem, when possible. Replace parts, if necessary. If the problem is not resolved, proceed to Test Step 3.
3. Check the Termination Resistors for the CAN Data Link Note: Perform this test only if you are troubleshooting a problem with the CAN data link. A. At the service tool connector, measure the resistance between the terminals for the CAN data link. The resistance should be between 45Ω to 75Ω.	Resistance	Result: The termination resistors are OK. There is an intermittent problem in a connector or in the harness. Repair: Repair the problem. Result: The resistance is approximately 120Ω. There is a problem with a termination resistor. Repair: At least one measurement is less than 5Ω. The wiring for a data link has a short circuit. Determine the cause of the missing termination resistor. Repair the problem, when possible. Replace parts, if necessary. Verify that the problem is resolved. Result: The resistance is greater than 140Ω. There is a problem with both termination resistors. Repair: Determine the cause of the problem. Repair the problem, when possible. Replace parts, if necessary.

If the problem is not resolved, contact your Technical Communicator (TC). For further assistance, the TC can confer with the Dealer Solutions Network (DSN).