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| Illustration 1 | g02729315 |
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Typical Cat Data Link connections | |
Note: The illustration for the Cat Data Link connections may not represent all connections for all components of all machines covered by this manual. Refer to the electrical system schematic for your machine to verify the Cat Data Link connections.
This diagnostic code is recorded when the Brake ECM does not receive expected information from the "Transmission ECM" for more than 5 seconds.
System Response:
This failure results in events that are logged against an ECM that cannot be explained directly. The Brake ECM cannot communicate with the "Transmission ECM" or the ECM appears to communicate intermittently.
Test Step 1. VERIFY THE HARDWARE AND THE SOFTWARE PART NUMBERS.
- Verify that the following information is correct:
- The part number of the flash software for the Brake ECM
- The part number of the flash software for the "Transmission ECM"
- The part number of the Brake ECM
- The part number of the "Transmission ECM"
Note: Consult your Caterpillar Dealer for the correct part numbers of the flash software.
Expected Result:
All of the part numbers are correct.
Results:
- OK - All of the part numbers are correct. Proceed to Test Step 2.
- NOT OK - All of the part numbers are not correct.
Repair: The installed Brake ECM or the "Transmission ECM" have the wrong part number or the incorrect flash software is installed. Replace the incorrect Brake ECM or the "Transmission ECM" with a module that has the correct part number. Flash the correct software. See the Testing and Adjusting, "Electronic Control Module (ECM)-Flash Programming" section for additional information.
STOP
Test Step 2. INSPECT THE HARNESS CONNECTIONS.
- Turn the disconnect switch to the OFF position.
- Inspect all harness connections that are related to the Cat Data Link. Make sure that the connectors are clean and tight.
- Check the connectors for proper mating. Ensure that all the seals are present and in place.
- Check the harness for signs of damage or abrasion.
- Check the wires at the connector. Ensure that the wires are secured tightly into the connector. Take care not to pull the wire out of the connector.
- Check the exposed wires at the connectors for nicks or signs of abrasion.
- Check for moisture inside the connector.
- Check the connectors for dirty contacts or corroded contacts.
- Check each pin and check each socket of the machine harness connectors. Ensure that the contacts are properly installed. The contacts should mate correctly when the two pieces of the connector are placed together.
Expected Result:
The machine harness connectors are tight and free of corrosion.
Results:
- OK - The machine harness connectors are tight and free of corrosion. Proceed to Test Step 3.
- NOT OK - The machine harness connectors are in need of repair.
Repair: Repair or replace the machine harness.
STOP
Test Step 3. CHECK FOR SHORTS TO GROUND
- The disconnect switch remains in the OFF position.
- Disconnect the machine harness connectors from all electronic control modules that use the Cat Data Link.
- At the machine harness for the Brake ECM, measure the resistance between frame ground and connector contacts J1-10 (wire 893-GN(Green)) and J1-20 (wire 892-BR(Brown)) of the Cat Data Link circuit .
Expected Result:
The resistance is greater than 5000 ohms.
Results:
- OK - The resistance is greater than 5000 ohms. The harness circuit resistance is correct. Proceed to Test Step 4.
- NOT OK - The resistance is less than 5000 ohms. The machine harness has failed.
Repair: There is a short between frame ground and contacts J1-10 (wire 893-GN(Green)) and J1-20 (wire 892-BR(Brown)) of the Cat Data Link circuit in the machine harness. Repair or replace the machine harness.
STOP
Test Step 4. CHECK FOR SHORT TO THE +BATTERY CIRCUIT
- The disconnect switch remains in the OFF position.
- All related electronic control modules remain disconnected from the machine harness.
- At the machine harness connector for the Brake ECM, perform the checks that are listed here:
- Measure the resistance between the connector contact J1-31 (wire 176-RD(Red)) and connector contact J1-10 (wire 893-GN(Green)).
- Measure the resistance between connector contact J1-31 (wire 176-RD(Red)) and connector contact J1-20 (wire 892-BR(Brown)).
Expected Result:
The resistance is greater than 5000 ohms.
Results:
- OK - The harness circuit resistance is correct. Proceed to Test Step 5.
- NOT OK - The resistance is less than 5000 ohms. The machine harness has failed.
Repair: There is a short between the +battery circuit and contacts J1-10 (wire 893-GN(Green)) and J1-20 (wire 892-BR(Brown)) of the Cat Data Link circuit in the machine harness. Repair or replace the machine harness.
STOP
Test Step 5. CHECK FOR OPEN HARNESS
- The disconnect switch remains in the OFF position.
- All related electronic control modules remain disconnected from the machine harness.
- Check the resistance of the Cat Data Link circuit in the machine harness:
- Measure the resistance between connector contact J1-10 (wire 893-GN(Green)) of the Brake ECM and connector contact J1-10 (wire 893-GN(Green)) of the "Transmission ECM".
- Measure the resistance between connector contact J1-20 (wire 892-BR(Brown)) of the Brake ECM and connector contact J1-20 (wire 892-BR(Brown)) of the "Transmission ECM".
Expected Result:
The resistance measures less than 5 ohms.
Results:
- OK - The resistance is less than 5 ohms. The Cat Data Link circuit in the machine harness is correct. Proceed to Test Step 6.
- NOT OK - The resistance is greater than 5 ohms. The machine harness has failed.
Repair: The Cat Data Link circuit is open in the machine harness. Repair or replace the machine harness.
STOP
Test Step 6. CHECK FOR ADDITIONAL DIAGNOSTIC CODES FOR THE OTHER ELECTRONIC CONTROL MODULES.
- Turn the key start switch and the disconnect switch to the OFF position.
- One at a time, reconnect the electronic control modules that use the Cat Data Link.
- Turn the disconnect switch and the key start switch to the ON position.
- After each of the electronic control modules has been reconnected, check for diagnostic codes that are logged against that electronic control module.
Expected Result:
Diagnostic codes are not present for the other electronic control modules.
Results:
- OK - Diagnostic codes are not present for the other electronic control modules. The "Transmission ECM" has failed.
Repair: A failure of the ECM is unlikely. Exit this procedure and perform this procedure again. If the failure is not found, replace the ECM.
STOP
- NOT OK - Diagnostic codes are present for the other electronic control modules. The Brake ECM has failed.
Repair: A failure of the Brake ECM is unlikely. Exit this procedure and perform this procedure again. Prior to replacing an ECM, always contact the Technical Communicator at your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the ECM requires replacement, refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace".
STOP