HOUSING AS-REGULATOR 4172768 - Caterpillar

Illustration 1 g01240008
CAN Data Link connectionsThe ECM has two CAN data link circuits that are internally connected in the ECM. This diagnostic code is recorded when the ECM does not receive the expected information on the CAN data link. A CID 0246 diagnostic code is recorded whenever a diagnostic code that is related to the CAN data link occurs. The possible causes of this diagnostic code are listed:
A poor electrical connection at a machine harness connector
A terminal resister is faulty.
A circuit in the CAN data link is shorted to ground.
The CAN data link circuit in the machine harness is shorted to the +battery circuit.
The CAN data link circuit in the machine harness is open.Test Step 1. CHECK FOR OTHER CODES
Check for similar diagnostic codes that are logged against other electronic control modules. If a similar diagnostic code is found, exit this test and perform the corresponding procedure(s) for the other diagnostic codes that are shown.Expected Result:Other diagnostic codes are showing.Results:
YES - Exit this procedure and perform the diagnostic procedure for the diagnostic codes that are shown. STOP
NO - There are no other related diagnostic codes. Proceed to Test Step 2. Test Step 2. INSPECT THE HARNESS CONNECTORS
Turn the key start switch and the disconnect switch to the OFF position.
Refer to the complete machine Electrical System Schematic for your machine. Inspect all of the connections that are involved in both CAN data link circuits.
Ensure that all connections are clean, secure and in good condition.Expected Result:The machine harness connections are correct.Results:
OK - The machine harness connections are correct. Proceed to Test Step 3.
NOT OK - One or more of the machine harness connections are not correct. Repair: Repair or replace any bad contacts, connectors or wires that are not in good condition in the machine harness.STOPTest Step 3. CHECK THE TERMINAL RESISTERS IN THE CIRCUITSThe key start switch and the disconnect switch remain in the OFF position.
At the Machine ECM, disconnect the machine harness connectors J1 and J2 connector from the ECM.
At the J2 connector, measure the circuit resistance between contact J2-56 (wire F711-GN) and contact J2-70 (wire F712-GY).
At the J2 connector, measure the circuit resistance between contact J2-67 (wire F711-GN) and contact J2-68 (wire F712-GY).Expected Result:The circuit resistance is approximately 120 ohms.Results:
OK - The circuit resistance is approximately 120 ohms for each circuit. The terminal resisters are correct. Proceed to Test Step 4.
NOT OK - One or both of the circuit resistance measurements is not approximately 120 ohms. The terminal resister for the involved circuit could be faulty or there could be an open or a short in the machine harness.Repair: Disconnect the terminal resistors from the circuit. At the resister contacts, measure the resistance between contact A and contact B. The measurement should be approximately 120 ohms. Replace any resister that is not correct. If the terminal resisters are not faulty, proceed to Test Step 4.Test Step 4. CHECK FOR A SHORT TO GROUNDNote: Perform this Test Step on one of the CAN data link circuits at a time,