HOSE ASSEM. 6P8112 - Caterpillar

This procedure is used for the following diagnostic codes:
296-09 Unable to Communicate with Transmission ECM
296-12 Transmission ECM FailedThe Cat Data Link is used for communication between electronic modules. The Cat Data Link is used to communicate information from the Electronic Control Module (ECM) to other electronic systems. The ECM sends information to the electronic dash displays in order to communicate the engine's operating status to the operator of the machine. The Cat Data Link is used for programming and troubleshooting the ECM.The ECM communicates with the Caterpillar Electronic Technician (ET) in order to share status information and diagnostic information. Cat ET can also be used to configure the ECM parameters. This information will not be available if communication fails between the ECM and Cat ET.
Illustration 1 g01259806
Schematic for the Cat Data Link (typical example)
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Terminals at the P1 ECM connector for the Cat Data Link
(P1-8) Cat Data Link +
(P1-9) Cat Data Link −
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J1/P1 ECM connectors (typical left side engine view)
Test Step 1. Inspect the Electrical Connectors and the Wiring
Remove electrical power from the engine ECM.
Thoroughly inspect the J1/P1 ECM connectors. Inspect all of the connectors to other modules that are on the Cat Data Link. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.
Check the allen head screw for each of the ECM connectors for the proper torque. Refer to the diagnostic functional Troubleshooting, "Electrical Connectors - Inspect".
Check the harness and the wiring for abrasion and for pinch points. Expected Result:All of the connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion and of pinch points.Results:
OK - The harness and connectors appear to be OK. Proceed to Test Step 2.
Not OK - The connectors and/or wiring are not OK.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem.STOPTest Step 2. Check for Shorts in the Harness
Disconnect the J1/P1 ECM connectors.
Disconnect all control modules from the Cat Data Link.
Disconnect Cat ET from the service tool connector . Note: Wiggle the harness during the following measurements in order to reveal an intermittent condition.
Measure the resistance from P1-8 to every terminal on the P1 ECM connector.
Measure the resistance from P1-8 to the chassis ground.
Measure the resistance from P1-9 to every terminal on the P1 ECM connector.
Measure the resistance from P1-9 to the chassis ground. Expected Result:Each check of the resistance indicates an open circuit.Results:
OK - Each check of the resistance indicates an open circuit. There does not appear to be a short in the harness. Proceed to Test Step 3.
Not OK - At least one check of the resistance does not indicate an open circuit.Repair: There is a short circuit in one of the harnesses. There may be a problem