Use this procedure to troubleshoot a suspected problem with the Cat Data Link or use this procedure if one of the diagnostic codes in Table 1 is active or easily repeated.
| Diagnostic Codes Table | ||
|---|---|---|
| Description | Conditions which Generate this Code | System Response |
| 590-9 Engine Control Module : Abnormal Update Rate | The master Electronic Control Module (ECM) has not received the last ten messages that were expected from the optional display panel over the Cat Data Link. | The code is logged. The alarm output is activated. The shutdown output is activated. The engine is shut down. |
| 1042-9 ITSM : Abnormal Update Rate | The master ECM has not received the last ten messages that were expected from the Integrated Temperature Sensing Module (ITSM) over the Cat Data Link. | The code is logged. The alarm output is activated. |
| 1636-9 (Slave) Engine #2 Electronic Control Module : Abnormal Update Rate | The ECM has not received the last ten messages that were expected from the slave ECM over the Cat Data Link. | The code is logged. The alarm output is activated. The shutdown output is activated. The engine is shut down. |
The Cat Data Link is used to provide communication between the following components:
- Master ECM
- Slave ECM
- ITSM
- Service tool
- Advisor Monitor Display
- Customer installed components
Each ECM, the ITSM, and the Advisor module communicate with Caterpillar Electronic Technician (ET) via the Cat Data Link. The Cat Data Link consists of two wires that are a twisted pair.
The most likely cause of a diagnostic code for the Cat Data Link are an open circuit or a short circuit. Connector terminals that are not fully seated in the connector body can create an open circuit condition. Be careful not to interchange the polarity of the wires for the data link in a connector. The Cat Data Link will not operate if the polarity of the wires are interchanged in a connector.
Communications over the Cat Data Link will fail if a module is not receiving power. This can happen if there is a problem with the power supply wiring for the module. Refer to the appropriate circuit test in this manual in order to check for power at the module before you troubleshoot a problem with the data link.
Communications over the Cat Data Link can fail if a module is programmed with the wrong flash file, or if a module has not been programmed with a flash file. The following modules utilize flash programming to update the module's software:
- Master ECM
- Slave ECM
- ITSM
- Advisor Monitor Display
Verify that all modules have been programmed with the most current flash file.
Harness Code for the Slave ECM
The harness inside the terminal box for the slave ECM incorporates a jumper wire that sets the harness code for the slave ECM. The harness code is set by a jumper wire across terminals J3-29 and J3-60. The ECM detects the jumper wire and a unique identification code is used by the ECM to communicate over the data link. This jumper allows the ECM to be identified as the slave ECM while the ECM communicates to other modules over the data link.
The harness code is necessary for the different modules to communicate over the Cat Data Link. If the connection for the harness code's jumper wire fails, Cat ET will display "Duplicate Type on data link. Unable to Service".
 | |
| Illustration 1 | g01588414 |
Typical schematic for the Cat Data Link | |
Test Step 1. Inspect the Electrical Connectors and the Wiring
- Turn the engine control switch to the OFF/RESET position. Remove the electrical power from the engine.
- Thoroughly inspect connectors (1 through 10). Inspect the twisted pair wiring that is in the harness between each of the modules. Refer to Troubleshooting, "Electrical Connectors - Inspect".
 | |
| Illustration 2 | g01418068 |
Location of the connectors at the ITSM that are for the Cat Data Link (front engine view) (1) Control harness connectors to the master ECM for the Cat Data Link | |
 | |
| Illustration 3 | g01449354 |
Location of the connectors at the advisor monitor display (2) Connectors for the advisor monitor display (3) Service tool connector | |
 | |
| Illustration 4 | g01418174 |
Location of the connectors at the terminal box for the master ECM that are for the Cat Data Link (left front engine view) (4) J1/P1 ECM connectors for the master ECM (5) J5/P5 customer connectors (6) Service tool connector (7) J8/P8 control harness connectors (8) J10/P10 connectors for the advisor monitor display | |
 | |
| Illustration 5 | g01418069 |
Location of the connectors at the terminal box for the slave ECM that are for the Cat Data Link (right side engine view) (9) J3/P3 ECM connectors for the slave ECM (10) J11/P11 control harness connectors for the harness to the master ECM | |
- Perform a 45 N (10 lb) pull test on each of the wires in the circuit for the Cat Data Link.
 | |
| Illustration 6 | g01418140 |
Terminal locations at the P1 ECM connector that are for the Cat Data Link (P1-8) Cat Data Link + (P1-9) Cat Data Link − | |
 | |
| Illustration 7 | g01418158 |
Terminal locations at the P3 ECM connector that are for the Cat Data Link (P3-8) Cat Data Link + (P3-9) Cat Data Link − (P3-29) Harness code (jumper connector location) (P3-60) Harness code (jumper connector location) | |
 | |
| Illustration 8 | g01418153 |
Terminal locations at the P5 customer connector that are for the Cat Data Link (P5-66) Cat Data Link + (P5-67) Cat Data Link − | |
 | |
| Illustration 9 | g01418160 |
Terminal locations at the P8 connector that are for the Cat Data Link (P8-a) Cat Data Link − (slave ECM) (P8-e) Cat Data Link + (ITSM) (P8-f) Cat Data Link − (ITSM) (P8-R) Cat Data Link + (slave ECM) | |
 | |
| Illustration 10 | g01418163 |
Terminal locations at the P10 connector that are for the Cat Data Link (P10-D) Cat Data Link + (P10-I) Cat Data Link − | |
 | |
| Illustration 11 | g01418167 |
Terminal locations at the P11 connector that are for the Cat Data Link (P11-A) Cat Data Link + (P11-B) Cat Data Link − | |
 | |
| Illustration 12 | g01418169 |
Terminal locations at each of the service tool connectors that are for the Cat Data Link (Terminal D) Cat Data Link + (Terminal E) Cat Data Link − | |
 | |
| Illustration 13 | g01418170 |
Terminal locations at the control harness connectors of the ITSM that are for the Cat Data Link (Terminal J) Cat Data Link + (Terminal N) Cat Data Link − | |
- Check the torque of the allen head screws for each of the ECM connectors and of the customer connector. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
- Check the harness and the wiring for abrasion and for pinch points from the terminal box to the other connections that are part of the Cat Data Link.
Expected Result:
All connectors, pins, and sockets are connected properly. The connectors and the wiring do not have corrosion, abrasion, or pinch points.
Results:
- OK - The connectors and wiring appear to be OK. Proceed to Test Step 2.
- Not OK - The connectors and wiring are not in good condition and/or at least one connection is not OK.
Repair: Repair the problem. Replace parts, if necessary. Verify that the repair has eliminated the original problem.
STOP
Test Step 2. Use Cat ET to Check Communications over the Cat Data Link
- Verify that the engine control switch is in the OFF/RESET position. Verify that the electrical power is removed from the engine.
- Connect Cat ET to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools".
- Turn the engine control switch to the STOP position. Restore the electrical power to the engine.
- Select the "File/Select ECM" menu on the Cat ET. Verify that all of the modules are displayed on the "ECM Selector" screen.
Verify that the following diagnostic codes are not activated.
- 590-9 Engine Control Module abnormal update rate
- 1042-9 ITSM abnormal update rate
- 1636-9 (Slave) Engine #2 Electronic Control Module abnormal update rate
Note: If Cat ET displays "Duplicate Type on data link. Unable to Service", there is probably a problem with the harness inside the terminal box for the slave ECM. Set the engine control switch to the OFF/RESET position. Remove the electrical power from the engine. Disconnect the J3/P3 ECM connector at the terminal box for the slave ECM. Check the continuity between terminals J3-29 and J3-60. Verify that the jumper wire has continuity. Make repairs, as needed.
- 590-9 Engine Control Module abnormal update rate
Expected Result:
All of the modules are displayed on the "ECM Selector" screen. There are no active diagnostic codes for the Cat Data Link.
Results:
- OK - All of the modules are displayed on the "ECM Selector" screen. There are no active diagnostic codes for the Cat Data Link.
Repair: The problem appears to be resolved. If any of the above codes are logged and the engine is not running properly, refer to Troubleshooting, "Symptom Troubleshooting".If any of the above codes are logged and the engine is running properly, there may be an intermittent problem in a connector or in the harness wiring. Refer to Troubleshooting, "Electrical Connectors - Inspect" for information that is related to troubleshooting intermittent electrical problems.
STOP
- Not OK - At least one of the modules is not displayed on the "ECM Selector" screen. There may be an active diagnostic code for the Cat Data Link. Proceed to Test Step 3.
Test Step 3. Check for Continuity of the Cat Data Link in the Wiring Harness
- Turn the engine control switch to the OFF/RESET position. Remove the electrical power from the engine.
- Disconnect Cat ET from the service tool connector.
- Disconnect the following connectors:
- P1 connector from the master ECM
- P3 connector from the slave ECM
- Control harness connector from the ITSM
- Harness connector from the advisor monitor display (if equipped)
- P1 connector from the master ECM
- Disconnect any wiring that may be connected to terminals P5-66 and P5-67 at the customer connector.
- Use a multimeter to check for continuity between the points that are listed in Table 2. During each measurement, wiggle the wires in the harness in order to check for an intermittent electrical problem. Be sure to wiggle the wires near each of the connectors. Check for continuity of the wiring for the Cat Data Link:
Show/hide table
Table 2 Continuity Checks for the Cat Data Link Connector and Terminal Connector and Terminal P1-8 (Cat Data Link +) P3-8 P5-66 Terminal D at the service tool connectors Terminal J at the harness connector for the ITSM Terminal 31 at the advisor monitor display P1-9 (Cat Data Link −) P3-9 P5-67 Terminal E at the service tool connectors Terminal N at the harness connector for the ITSM Terminal 32 at the advisor monitor display
- Also, check that the wiring for the Cat Data Link is not shorted to ground:
Check for continuity between P1-8 and the ECM ground strap.
Check for continuity between P1-9 and the ECM ground strap.
Expected Result:
The Cat Data Link is continuous to the other connectors in the circuit. The Cat Data Link is not shorted to ground.
Results:
- OK - Each check of the resistance for the Cat Data Link is within the specification.
Repair: The wiring for the Cat Data Link appears to be OK.Perform the following procedure:
- Connect the following connectors:
- P1 ECM connector
- P3 ECM connector
- Harness connector at the ITSM
- Connector for the advisor monitor display (if equipped)
- P1 ECM connector
- Connect Cat ET to the service tool connector.
- Restore the electrical power to the engine. Turn the engine control switch to the STOP position.
- Verify that Cat ET is able to communicate with each of the modules.
- If Cat ET is unable to communicate with a module, there may be a problem with the supply voltage to the module. Ensure that each of the modules are receiving the supply voltage.
- If the problem is not resolved, there may be a problem with the wiring for the Cat Data Link between the J5 connector and the customer's equipment. Verify that the wiring for the Cat Data Link between the J5 connector and the customer's equipment is working properly.
- If the problem is not resolved, there may be a problem with the module that is not communicating with Cat ET.
Temporarily replace the module that is not communicating. Refer to Troubleshooting, "ECM - Replace" or Troubleshooting, "Control Module - Replace". Verify that the problem is resolved.
If the problem is resolved with the new module, reinstall the original module and verify that the problem returns. If the new module works correctly and the original module does not work correctly, replace the original module. Refer to Troubleshooting, "ECM - Replace" or Troubleshooting, "Control Module - Replace".
STOP
- Connect the following connectors:
- Not OK - At least one check of the resistance for the Cat Data Link is incorrect. There is a problem with the wiring for the Cat Data Link.
Repair: Repair the connection and/or the wire, when possible. Replace parts, if necessary. Verify that the problem is resolved.
STOP