525C Wheel Skidder, 535C Wheel Skidder and 545C Wheel Skidder Machine Systems Caterpillar

Illustration 1	g01246429
Directional Switch connections

This diagnostic code is associated with the transmission direction switch. The switch provides three switch to ground type inputs to the ECM. Two contacts are open and the third contact is grounded during normal operation. This FMI 02 means that the ECM has determined that one or more of the input signals is erratic or intermittent.

Possible causes of this diagnostic code are listed:

• The ground circuit is not correct.

• The switch is not working correctly.

• One of the switch circuits is grounded.

• One of the switch circuits is shorted to a +battery source.

• The ECM has failed. This is unlikely.

Note: The following test procedure may create other diagnostic codes. Ignore these diagnostic codes and clear the diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 0623 FMI 02 is active before performing this procedure.

Test Step 1. CHECK THE GROUND CIRCUIT OF THE SWITCH

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

2. Disconnect the machine harness connector from the steering control.

3. At the machine harness connector for the steering control, measure the resistance between contact 2 (wire 202-BK) of the machine harness and frame ground.

Expected Result:

The resistance is less than 5 ohms.

Results:

• OK - The resistance is less than 5 ohms. The circuit is correct. Proceed to Test Step 2.

• NOT OK - The resistance is greater than 5 ohms. The circuit is open. The machine harness has failed.

  Repair: The ground circuit wire 202-BK has a bad connection or an open in the machine harness. Refer to the complete machine Electrical System Schematic. Examine all of the connectors that are in the circuit. Ensure that the connections are clean, secure and in good condition. Repair the machine harness or replace the machine harness.

  STOP

Test Step 2. CHECK THE OPERATION OF THE SWITCH

The key start switch and the disconnect switch remain in the OFF position.

1. The machine harness remains disconnected from the steering control.

2. Move the switch to the NEUTRAL position.

3. At the steering control connector, measure the resistance from the common contact 2 to contact 1. Repeat the resistance measurement from common contact 2 to contact 3 and then to contact 4. Record the measurements.

4. Move the switch to the FORWARD position and repeat Step "C". Record the measurements.

5. Move the switch to the REVERSE position and repeat Step "C". Record the measurements.

Expected Result:

At each switch position, each resistance measurement from common contact 2 to the other switch contacts should compare correctly with the table at the beginning of this procedure.

Results:

• YES - Each resistance measurement in each switch position is correct according to the table. The switch is operating correctly. Proceed to Test Step 3.

• NO - One or more of the resistance measurements is not correct according to the table. The switch has failed.

  Repair: Replace the switch.

  STOP

Test Step 3. CHECK THE SWITCH CIRCUITS FOR A SHORT TO GROUND

The disconnect switch and the key start switch remain in the OFF position.

1. Disconnect the machine harness connectors J1 and J2 from the ECM.

2. At the ECM machine harness connector J2, measure the resistance from contact J2-23 (wire G763-PU) to frame ground.

3. At the ECM machine harness connector J2, measure the resistance from contact J2-28 (wire G755-GY) to frame ground.

4. At the ECM machine harness connector J2, measure the resistance from contact J2-49 (wire G750-BU) to frame ground.

Expected Result:

Each resistance measurement is greater than 5000 ohms.

Results:

• YES - Each resistance measurement is greater than 5000 ohms. The harness is correct. Proceed to Test Step 4.

• NO - One or more of the resistance measurements is less than 5000 ohms. There is a short in the machine harness.

  Repair: The short is in the switch input circuit that had the low resistance to ground. The circuit is shorted to a ground source in the machine harness. Refer to the complete machine Electrical System Schematic. Examine all connections in the sender circuit for a possible short to ground. Repair the machine harness or replace the machine harness.

  STOP

Test Step 4. CHECK THE SWITCH CIRCUITS FOR A SHORT TO +BATTERY

The key start switch and the disconnect switch remain in the OFF position. The steering control remains disconnected from the machine harness connector.

1. Disconnect the machine harness connectors J1 and J2 from the ECM.

2. At the machine harness J2 connector, measure the resistance from contact J2-23 (wire G763-PU) to all +battery (wire 170-RD) contacts that are used on the ECM connectors. The + battery contacts are J2-31, J2-38, J2-39 and J2-47.

3. Repeat the above Step with the two other switch input circuits at contact J2-28 (wire G755-GY) and J2-49 (wire G750-BU).

Expected Result:

Each resistance measurement is greater than 5000 ohms.

Results:

• OK - Each resistance measurement is greater than 5000 ohms. The switch input circuits are not shorted in the harness. Proceed to Test Step 5.

• NOT OK - One or more of the resistance measurements is less than 5000 ohms.

  Repair: The switch input circuit with the low resistance measurement is shorted to a +battery source in the machine harness. Refer to the complete machine Electrical System Schematic. Check the connectors that are in the involved circuits. Ensure that all connections points for the circuits that show a short are clean, secure and in good condition. Repair the machine harness or replace the machine harness.

  STOP

Test Step 5. CHECK THE STATUS OF THE DIAGNOSTIC CODE

1. Inspect the harness connectors and clean the contacts of the harness connectors and check the wires for damage to the insulation that is caused by excessive heat, battery acid, or chafing.

2. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit.

3. Reconnect all harness connectors making sure that the connectors are fully seated and the clips for each connector are completely fastened.

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

5. Operate the machine.

6. Determine if the CID 0623 FMI 02 diagnostic code is active.

Expected Result:

The CID 0623 FMI 02 diagnostic code is active.

Results:

• YES - The CID 0623 FMI 02 diagnostic code is active. The problem has not been corrected.

  Repair: Check the circuit again. Use the Caterpillar Electronic Technician (ET) service tool, if available, in order to perform a "Wiggle Test" on the machine wiring harness. The wiggle test can detect momentary or intermittent shorts or opens in the machine wiring harness.If a problem is not found in the machine harness, replace the direction switch. If the problem is still present after replacement of the switch, the ECM may be faulty.Exit this procedure and perform the diagnostic code procedure again. If the problem persists, the ECM may have failed. Prior to replacing an ECM, always contact your dealership's Technical Communicator for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the cause of the diagnostic code is not found, replace the ECM. See Troubleshooting, "Electronic Control Module (ECM) - Replace".

  STOP

• NO - The CID 0623 FMI 02 is not active. The problem 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