BUSHING 2964663 - Caterpillar

System Operation Description:Use this procedure under the following situation:Use this procedure if the Caterpillar Electronic Technician (ET) will not power up. Use this procedure if the Cat ET will not communicate with the Engine Control Module (ECM) through the cab data link connector.The following background information is related to this procedure:The ATA data link (American Trucking Association) is the standard data link that is used by the ECM to communicate with electronic service tools. The SAE specification J1587 defines the format of the messages and data that is being communicated. The SAE specification J1708 defines the hardware requirements and the protocol of the serial communications. The Cat ET is an example of one of the electronic service tools. Some electronic dashboards use this data link to receive information. Some automatic transmissions also receive information from this data link.
Illustration 1 g01063985
The ECM provides the following two terminal connections for the ATA data link at the ECM vehicle harness connector J1:
J1-1 (J1587 Data Link Negative)
J1-7 (J1587 Data Link Positive)The vehicle OEM provides twisted pair wiring from the ECM to the cab data link connector.There are potentially several devices that are installed in the vehicle. These devices are connected to the ATA data link at one time. These devices include dash displays, trip recorders and transmission controls. These devices may cause problems with the data link. These problems can disrupt communications to the engine ECM and from the engine ECM.CommunicationWhen the keyswitch is in the OFF position, the ECM may communicate with Cat ET. The communications may be disrupted and the communications may require frequent reconnection. In order to avoid this problem, turn the ignition keyswitch to the ON position when Cat ET is being used.Cat ET 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 latest version of Cat ET has not been installed or this message will indicate that the software in the ECM is newer than the software for Cat ET.
Illustration 2 g01063986
Schematic
Illustration 3 g01063988
ECM pin locationsTest Step 1. Inspect the Electrical Connectors and the Wiring
Thoroughly inspect the following electrical connectors:
ECM vehicle harness connector J1/P1
Cab data link connector
Firewall bulkhead connector
Electronic service tool connectors
ATA data link (terminal 1 and terminal 7) in the connectorsRefer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the ATA data link.
Check the allen head screws for each of the ECM connectors for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and wiring for abrasion and pinch points from the connector to the ECM.Refer to Illustration 3.Expected Result:All connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion or of pinch points.Results:
OK - Proceed to Test Step 2.
Not OK - Repair: Perform the following repair:Repair the connectors