450E Backhoe Loader Machine Electronic Control System MID 039 - CID 2736 - FMI 03 Caterpillar

Conditions Which Generate This Code:

Illustration 1	g01317373

This diagnostic code is associated with the Hoe Auxiliary Continuous Flow Switch. This switch has two inputs to the ECM: normally open (wire M937-GN) and normally closed (wire M936-BR). During normal operation, one switch input is open and the other input is grounded. If each input is in the same state, the ECM will detect a diagnostic code. This diagnostic code is detected when both switch inputs are open at the same time.

The possible causes of this diagnostic code are listed:

• Short to the + battery terminal.

• The circuit is open.

• A failed switch

• The ECM may have failed.

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 2736 FMI 03 is active before performing this procedure.

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

Note: Before performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure, and in good condition. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure.

Test Step 1. CHECK THE CIRCUIT FOR THE SWITCH.

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

2. Disconnect the J1 machine harness connector from the ECM.

3. At the J1 machine harness connector, measure the resistance from contact J2-38 (wire M937-GN) to contact J2-55 (wire M936-BR) with the switch in the Enabled position and the Disable positions.

4. At the J1 machine harness connector, measure the resistance from contact J2-55 (wire M936-BR) to contact J2-38 (wire M937-GN) with the switch in the Disabled position and the Enabled position.

Expected Result:

The resistance should measure between approximately 5 ohms and greater than 5000 ohms for each switch position.

Results:

• YES - The resistance is correct for each measurement. Proceed to test step 3.

• NO - The resistance measurement is greater than 5000 ohms for one or both measurements. The harness or the switch has failed. Proceed to test step 2.

Test Step 2. CHECK FOR A SHORT.

1. Disconnect the switch from the harness.

2. At the J2 machine harness connector, measure the resistance from contact J2-38 and contact J2-55 to all other J1 and J2 contacts.

Expected Result:

The resistance measurement should be greater than 5000 ohms for each measurement.

Results:

• OK - The resistance measurement is greater than 5000 ohms for each measurement.

  Repair: Replace the switch.

  Proceed to Test Step 3.

• NOT OK - The resistance measurement is not greater than 5000 ohms for one or more measurements.

  Repair: The short is in the circuit with the low resistance measurement. Repair the harness or replace the harness. Verify that the problem has been corrected.

  STOP

Test Step 3. CHECK IF THE DIAGNOSTIC CODE REMAINS

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

2. Reconnect all the 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 2736 FMI 03.

Expected Result:

The CID 2736 FMI 03 is active.

Results:

• YES - The CID 2736 FMI 03 is active. The diagnostic code has not been corrected. The ECM may have failed.

  Repair: Prior to replacing an ECM, always contact your dealership Technical Communicator for possible consultation with AVSpare. This consultation may greatly reduce repair time. If the ECM must be replaced, refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace".

  STOP

• NO - The CID 2736 FMI 03 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. Resume normal machine operation.

  STOP