FILTER 3I1220 - Caterpillar

Use this procedure if the electronic service tool will not communicate with the ECM through the data link.The following background information is related to this procedure:The data link is the standard data link that is used by the ECM to communicate with the electronic service tool.The ECM provides multiple connections for the data link. The technician must ensure that the correct connector is being tested. The connection that is used depends on the application.If the diagnostic connector is off the engine, the positive data link signal will be from P1:8 to pin "D" of the diagnostic connector. The negative data link signal will be from P1:9 to pin "E" of the diagnostic connector.If the diagnostic connector is on the engine, the positive data link signal will be from P2:20 to pin "D" of the diagnostic connector. The negative data link signal will be from P2:28 to pin "E" of the diagnostic connector.The following information refers to the pin number. Ensure that the correct connector is used.CommunicationThe electronic service tool may indicate the following error message:The version of the ECM is not recognized and the integrity of the changed parameters and displayed data is not guaranteed.This message will indicate that the version of the software that is in the electronic service tool is obsolete. Install the latest version of the software for the electronic service tool to rectify the fault.
Illustration 1 g06151593
Schematic of the diagnostic connector and the data link connector for a diagnostic connector that is mounted off engine
Illustration 2 g06151589
Schematic of the diagnostic connector and the data link connector for an engine-mounted diagnostic connector
Illustration 3 g02028056
P1 pin locations for the diagnostic connector
(8) Data link +
(9) Data link -
Illustration 4 g02090413
Typical view of the P2 pin locations for the diagnostic connector
(20) Data link +
(28) Data link -
(53) Voltage supply (diagnostic connector)
(54) Return (diagnostic connector)Complete the procedure in the order in which the steps are listed.
Table 1
Troubleshooting Test Steps Values Results
1. Inspect Electrical Connectors and Wiring
A. Turn the keyswitch to the OFF position.
B. Inspect the connectors in the circuit for the data link.
Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
C. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the CAN data link.
D. Check the screw for the P1 and P2 ECM connectors for correct torque of 6 N m (53 lb in).
E. Check all the wiring associated with the data link for abrasions and pinch points.
Damaged wire or connector
Result: A damaged wire or damaged connector was found.
Repair: Repair the damaged wire or the damaged connector.
Use the electronic service tool to clear all logged diagnostic codes. Verify that the repair eliminates the fault.
Result: A damaged wire or damaged connector was not found.
Proceed to Test Step 2.
2. Determine the Type of Fault in the Data Link
A. Connect the electronic service tool to the diagnostic connector that is on the engine harness or on the application.
Repair: Turn the keyswitch to the ON position.
Power to the comms adapter
Result: The power lamp illuminates on the communications adapter. The