M313C, M315C, M316C, M318C, M318C MH, M322C and M322C MH Excavators Electronic System MID 039 - CID 0736 - FMI 06 Caterpillar

Conditions Which Generate This Code:

Illustration 1	g01158309
Schematic of the automatic engine speed control circuit

This diagnostic code is associated with the automatic engine speed control. The FMI 06 means that the machine ECM has commanded the circuit to be open but the engine ECM determines that the circuit is grounded. This information is sent from the engine ECM to the machine ECM on the Cat Data Link.

The possible causes of the diagnostic code are listed:

• The circuit is shorted to ground.

• The engine ECM has failed. This is unlikely.

• The machine ECM has failed. This is unlikely.

Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear these diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 736 FMI 06 is active before performing this procedure.

Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.

System Response:

When this diagnostic code is active, the automatic engine speed control is inoperative.

Test Step 1. CHECK THE WIRING HARNESS OF THE SENSOR FOR A SHORT TO GROUND.

1. Turn the key start switch and the disconnect switch to the OFF position.

2. Disconnect the machine harness from the machine ECM. Disconnect the harness from the engine ECM.

3. At the machine harness connector for the machine ECM, measure the resistance from contact J2-32 (wire H783-GN) to all contacts that are used in the machine harness connectors for the machine ECM.

Expected Result:

Each resistance measurement is greater than 5000 ohms.

Results:

• OK - Each resistance measurement is greater than 5000 ohms. The machine harness is correct. Proceed to Test Step 2.

• NOT OK - One or more resistance measurements is not correct. There is a short in the machine harness.

  Repair: The short is between contact J2-32 (wire H783-GN) and the circuit with the low resistance measurement. Repair the machine harness or replace the machine harness.

  Stop.

Test Step 2. CHECK THE OPERATION OF THE ENGINE ECM.

1. Reconnect the machine harness connectors to the machine ECM.

2. At the machine harness connector for the engine ECM, remove the H783-GN wire (contact 30). Use the proper extraction tool.

3. Insert a jumper wire into the empty contact 30. Ensure that the other end of the jumper wire does not contact any part of the machine.

4. Reconnect the machine harness connector to the engine ECM.

5. Turn the disconnect switch and the key start switch to the ON position.

6. Operate the machine. Turn on the automatic engine speed control. Move the boom and then stop all movement. Wait for the reduction of the RPM to idle.

Expected Result:

The engine never goes to low idle.

Results:

• OK - The engine never goes to low idle. Proceed to Test Step 3.

• NOT OK - The engine goes to low idle. The engine ECM has determined that contact 30 is grounded when the contact is open.

  Repair: The engine ECM may have failed. Reconnect wire H783-GN to contact 30 of the engine ECM. It is unlikely that the engine ECM has failed. Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found see the service manual for the engine for more troubleshooting information.

  Stop.

Test Step 3. CHECK THE ENGINE ECM.

1. While the engine is running, connect the jumper wire that is connected to contact 30 of the engine ECM to frame ground.

Expected Result:

The engine goes to low idle.

Results:

• OK - The engine goes to low idle. The engine ECM is operating correctly. Proceed to Test Step 4.

• NOT OK - The engine never goes to low idle. The engine ECM may have failed. Reconnect wire H783-GN to contact 30 of the engine ECM. It is unlikely that the engine ECM has failed. Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found see the service manual for the engine for more troubleshooting information. Stop.

Test Step 4. CHECK IF THE DIAGNOSTIC CODE REMAINS.

1. Inspect the contacts of the harness connectors and clean the connectors.

2. Reconnect all harness connectors.

3. Turn the disconnect switch and the key start switch to the ON position.

4. Operate the machine.

5. Check the status of the CID 0736 FMI 06.

Expected Result:

The CID 0736 FMI 06 is active.

Results:

• YES - The CID 0736 FMI 06 is active. The diagnostic code has not been corrected. The machine ECM may have failed.

  Repair: It is unlikely that the machine ECM has failed. Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, replace the machine ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".

  Stop.

• NO - The CID 0736 FMI 06 is not active. The diagnostic code does not exist at this time.

  Repair: The initial diagnostic code was probably caused by a poor electrical connection or a short at one of the harness connectors that was disconnected and reconnected. Resume normal machine operation.

  Stop.