793F CMD Off-Highway Truck Caterpillar

Illustration 1	g02792319
Cat and CAN data-link circuits

CID 0246 - FMI 14 indicates the VIMS^TM 3G Main ECM does not communicate over the CAN data-link properly and additional troubleshooting information is required.

Following are the possible causes of this communication loss.

• VIMS 3G Main ECM fuse failure

• Incorrect software

• Incompatible software

• Faulty harness

• Failed ECM

Use a calibrated digital multimeter for the following tests.

Test Step 1. CHECK THE VIMS^TM 3G MAIN ECM FUSE

1. Check the VIMS 3G Main ECM fuse with the multimeter.

Expected Result:

The fuse has failed.

Results:

• OK - The fuse has failed.

  Repair: Replace the fuse.

  If the new fuse fails, investigate and correct the cause.

  Ensure that the diagnostic code is no longer active.

  STOP

• NOT OK - The fuse has not failed. Proceed to Test Step 2.

Test Step 2. CHECK THE OTHER ECMS AND THE MONITORING SYSTEM FOR PROPER SOFTWARE VERSIONS

1. Use Caterpillar® Electronic Technician (Cat® ET) to verify software versions.

   Note: Consult your Cat dealer for the correct software part numbers.

Expected Result:

The proper compatible software versions are installed.

Results:

• OK - The proper compatible software versions are installed. Proceed to Test Step 3.

• NOT OK - The proper compatible software versions are not installed.

  Repair: Flash the proper software.

  Cycle the keyswitch to initialize the new software.

  Ensure that the diagnostic code is no longer active.

  STOP

Test Step 3. INSPECT THE HARNESS

1. Turn off the keyswitch.

2. Turn off the battery disconnect switch.

3. Inspect the harness for the following:

   1. Inspect the connectors, pins, and sockets for the following:

      • Cleanliness

      • Security

      • Proper mating

      • Seal condition

      • Moisture

      • Corrosion

      • Connector allen head screw for the proper torque of 2.25 ± 0.25 N·m (20 ± 2 lb in)

   2. Inspect the wires at the connector for the following:

      • Security

      • Nicks

      • Abrasion

      Note: Take care not to pull the wire out of the connector.

   3. Inspect the harness for the following:

      • Damage

      • Abrasion

      • Kinks

Expected Result:

The harness is in good condition.

Results:

• OK - The harness is in good condition. Proceed to Test Step 4.

• NOT OK - The harness is not in good condition.

  Repair: Repair or replace the harness.

  Ensure that the diagnostic code is no longer active.

  STOP

Test Step 4. CHECK THE HARNESS RESISTANCE

1. Turn off the keyswitch.

2. Disconnect the ECM from the harness.

3. Disconnect Cat ET from the service tool connector.

4. Measure the resistance at the VIMS 3G Main ECM connector between 34 and 50.

Expected Result:

The resistance is low.

Results:

• OK - The resistance is low. Proceed to Test Step 5.

• NOT OK - The resistance is high or open.

  Repair: Repair or replace the harness.

  STOP

Test Step 5. CHECK THE HARNESS FOR A SHORT

1. Measure the resistance at the following VIMS 3G Main ECM connector pins:

   1. Pin 34 and frame ground

   2. Pin 50 and frame ground

Expected Result:

The resistance is high or open.

Results:

• OK - The resistance is high or open

  Repair: Repair or replace the harness.

  STOP

• NOT OK - The harness is shorted.

  Repair: Repair or replace the harness.

  Proceed to Test Step 6.

Test Step 6. RECHECK FOR THE DIAGNOSTIC CODE

1. Connect the Cat® ET service tool to the service tool connector.

2. Turn on the battery disconnect switch.

3. Turn on the keyswitch.

4. Check Cat ET for an active CID 0246 - FMI 14 diagnostic code.

Expected Result:

CID 0246 - FMI 14 is not active.

Results:

• OK - CID 0246 - FMI 14 is not active.

  Repair: Reset the system and troubleshoot any active diagnostic codes.

  Correct other diagnostic codes.

  STOP

• NOT OK - CID 0246 - FMI 14 is active. A CAN-related ECM may have failed, however, ECM failure is unlikely.

  Repair: Perform the following:

  1. Exit this procedure.

  2. Perform this procedure again.

  3. If the failure is not found, contact your technical communicator.

     Reference: If ECM replacement is required, see the Testing and Adjusting, "Electronic Control Module (ECM) - Replace" Section of this manual.

  STOP