INSERT 1273598 - Caterpillar

Illustration 2 g06003452
Schematic of the Cat Data Link circuits
Note: The diagram above is a simplified schematic of the connections for the Cat data link circuits. The schematic is electrically correct. However, not all of the possible harness connectors are shown. Refer to the latest revision of the Electrical Schematic, UENR6729 for the complete schematic.Diagnostic Trouble Code Procedure
Note: Prior to beginning this procedure, inspect the harness connectors that are involved in this circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure, and in good condition. If a problem with a connection is found, correct the problem and verify that the diagnostic code is active before performing a troubleshooting procedure. For sensors powered via the fuse panel, check the condition of the appropriate fuse before beginning the troubleshooting procedure.
Table 3
Troubleshooting Test Steps Values Results
1. Identify The Active FMI Code Associated With The Cat Data Link
Code present. FMI 9, proceed to Test Step 2.
FMI 12 , proceed to Test Step 5.
FMI 14 , proceed to Test Step 7.
Begin Process For FMI 9 Troubleshooting HERE
2. Check The Data Link For An Open
A. Turn the key switch and the battery disconnect switch to the OFF position.
B. Disconnect the machine harness connector from the ECM.
C. At the disconnected connector for the ECM, connect a jumper wire between CAN positive contact and CAN negative contact.
D. Measure the resistance from the ECM.
The resistance measure less than 5 ohms. OK - The resistance is less than 5 ohms .
Proceed to Test Step 3.
NOT OK -The resistance measurement is greater than 5 ohms.
Repair: Repair or replace the machine harness.
Proceed to Test Step 6.
3. Check The Resistance Of The Data Link
A. Turn key start switch and disconnect switch OFF.
B. Disconnect the machine harness connector from the ECM.
C. At the disconnected harness connector of the ECM, measure the resistance between CAN positive contact and CAN negative contact.
The resistance reading is around 60 ohms. OK - The resistance measurement is approximately 60 ohms.
Proceed to Test Step 4.
NOT OK - The resistance measurement is not approximately 60 ohms.
Repair: Replace the resistors.
Proceed to Test Step 6.
4. Check The Data Link For A Short
A. Turn key start switch and disconnect switch OFF.
B. Disconnect all harnesses from the ECM.
C. At the ECM, measure the resistance between CAN positive contact and a ground point.
D. Measure the resistance between CAN positive contact and all of the other circuits that are used.
The resistance is greater than 4K ohms. OK - The resistance is greater than 4K ohms.
Proceed to Test Step 6.
NOT OK - One or more of the resistance measurements is less than 4K ohms .
Repair: Find the short circuit in the data link circuits in order to resolve this problem.
Proceed to Test Step 6.
Begin Process For FMI 12 Troubleshooting HERE
5. Verify The Hardware And The Software Part Numbers(1)
A. The part number of the flash software for the ECM.
B. The part number of the flash software for the "Monitor Display" ECM.
C. The part