D6N Track-Type Tractor Caterpillar

Illustration 1	g02666363
Blade Control Mode switch schematic

Illustration 2	g01930757
Blade Control Mode handle location

A CID 2755 is associated with the Blade Control Mode switch. An FMI 03 diagnostic code is recorded when the machine ECM reads the status of both inputs as open.

Possible causes for this diagnostic code are:

• Blade Control Mode switch failure.

• The "normally open" signal circuit (wire Y933-YL) is shorted to ground.

• The "normally closed" signal circuit (wire Y934-WH) is always shorted to ground.

• Machine ECM failure, but is most unlikely.

Note: Poor connections are often the cause of a problem in electrical circuits. Before performing this procedure, inspect all the machine harnesses and connectors involved in the circuit. Make sure to verify that all of the connections in the circuit are clean, secure, and in good condition. Correct any problems found with any of the connections. Verify the diagnostic code CID 2755 FMI 04 is still active, before continuing with this procedure.

Note: The following test procedure may create other diagnostic codes. Ignore all the created diagnostic codes now, but clear all those codes after the cause for the original diagnostic code has been corrected.

System Response:

A level 1 warning is generated.

Test Step 1. CHECK THE BLADE CONTROL MODE SWITCH.

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

2. Disconnect the harness connector from the Blade Control Mode switch.

3. Check for continuity between contact 10 and contact 5 of the switch.

4. Press the switch and then release the switch while you check for continuity.

5. Check for continuity between contact 11 and contact 5 of the switch.

6. Press the switch and then release the switch while you check for continuity.

Expected Result:

The continuity checks agree with Table1.

Results:

• YES - The continuity check agrees with the preceding Table. Go to Test Step 2.

• NO - The continuity check does not agree with the preceding Table. The switch has failed.

  Repair: Replace the joystick handle.

  Go to Test Step 3.

Test Step 2. CHECK THE BLADE CONTROL MODE SWITCH FOR A SHORT CIRCUIT TO GROUND.

1. The disconnect switch, and the key switch, remain in the OFF position.

2. The Blade Control Mode switch remains disconnected from the harness connector.

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

4. At the J2 ECM harness connector, check for continuity between contact J2-46 (wire Y933-YL) and frame ground.

5. Press and then release the switch, while you check for continuity.

6. Check for continuity between contact J2-47 (wire Y934-WH) and frame ground.

7. Press the switch and then release the switch while you check for continuity.

8. Check for continuity between contact J2-47 (wire Y934-WH) and contact J2-46 (wire Y933-YL).

Expected Result:

Each resistance is more than (+/-) 5000 ohms.

Results:

• YES - Each resistance is more than (+/-) 5000 ohms. There are no short circuits in the harness. Go to Test Step 3.

• NO - A resistance is less than (+/-) 5000 ohms. There is a short circuit in the harness.

  Repair: The wires with the low resistance are shorted in the harness. Repair or replace the harness.

  Go to Test Step 3.

Test Step 3. CHECK THE DIAGNOSTIC CODE STATUS.

1. Remove the jumper wires from the Blade Control Mode switch harness connector.

2. Reconnect all harness connectors. Make sure all the connectors are clean, and fully seated. Make sure that the clips for each connector are securely fastened.

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

4. Clear all inactive diagnostic codes.

5. Operate the machine.

6. Observe the status of the CID 2755 FMI 04 diagnostic code.

Expected Result:

The diagnostic code is no longer active.

Results:

• YES - The diagnostic code is no longer active and does not exist at this time. The problem has been corrected.

  Repair: Return machine to normal operation

  STOP

• NO - The diagnostic code is still active. The problem has not been corrected.

  Repair: If you have not inspected the harness connectors in a previous Test Step, do that now. Clean the contacts of the harness connectors. Check the wires for damage to the insulation caused by excessive heat, battery acid, or chafing.Perform a 45 N (10 lb.) pull test on each of the wires that are associated with the sensor circuit.Perform a "wiggle test" on the sensor circuit of the machine wiring harness, using the Caterpillar Electronic Technician service tool. The "wiggle test" can be used to detect open or shorted connections in the machine wiring harness.Reconnect all harness connectors. Make sure that the connectors are fully seated. Observe that the clips for each connector are securely fastened. Perform Test Step 3 again. If the problem has NOT been found, and the original code is still active, the machine ECM may have failed.Prior to replacing an ECM, always contact your Dealership Technical Communicator for possible consultation with Caterpillar, or with the Dealer Solutions Network. This consultation may greatly reduce repair time. If the ECM needs to be replaced, see Testing and Adjusting, "Electronic Control Module (ECM) - Replace".

  STOP