C4.4 and C6.6 Industrial Engines and Engines for Caterpillar Built Machines Caterpillar

Use this procedure under the following circumstances:

• Diagnostic code 1743-02 has been generated.

• Check if the mode selector switch operates correctly.

The mode selector switch inputs provide the operator with the ability to select a maximum of four different modes of operation. Different modes of operation can be used in a particular situation by giving the operator a means to select the most efficient method of completing the required work.

Each mode has a single fuel limit map, a rated speed, and a matched fuel delivery. Each mode also has a specific droop value for throttle 1 and throttle 2.

For C4.4 engines, refer to table 1 for a list of examples of different modes of operation.

For C6.6 engines, refer to table 2 for a list of examples of different modes of operation. Refer to table 3 for a list of mode switch connections.

Illustration 1	g01805358
Typical schematic for the mode selector switches

Illustration 2	g01805359
View of the pin locations on the P1 connector for the circuit for mode selection (35) Mode switch return (GND) (39) Mode switch 1 (46) Mode switch 2

Test Step 1. Inspect Electrical Connectors and Wiring

1. Turn the keyswitch OFF.

2. Thoroughly inspect the P1 connector. Thoroughly inspect the mode switch connectors, plugs and interconnections on the harness. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.

3. Perform a 45 N (10 lb) pull test on each of the wires in the P1 connector that are associated with the mode selector switches.

4. Check the screw for the ECM connector for the correct torque of 5.0 N·m (44 lb in).

5. Check the harness for abrasions and for pinch points from the battery to the ECM.

Results:

• OK - Proceed to Test Step 2.

• Not OK -

  Repair: Repair the connectors or the harness and/or replace the connectors or the harness. Ensure that all of the seals are correctly in place and ensure that the connectors are completely coupled.Use the electronic service tool in order to clear all logged diagnostic codes and then verify that the repair eliminates the fault.

  STOP

• - If the fault has not been eliminated proceed to Test Step 2.

Test Step 2. Check the Status of the Mode Selector Switch

1. Turn the keyswitch to the OFF position.

2. Connect the electronic service tool to the diagnostic connector.

3. Turn the keyswitch to the ON position.

4. Monitor the status screen on the electronic service tool. Cycle the mode switch to the ON position and to the OFF position.

Expected Result:

The switch status should change as you cycle the mode switches. When the switch is in the OFF position, the switch is open. When the switch is in the ON position, the switch is closed.

Results:

• OK -

  Repair: Verify that the status of the switch changes as the switch is cycled.

  STOP

• Not OK - There is a fault with the circuit for the mode selector switch. Proceed to Test Step 3.

Test Step 3. Insert a Jumper at the Suspect Mode Switch

1. Turn the keyswitch to the OFF position.

2. Perform the following procedure to test the circuit of mode selector switch No. 1. Place a jumper wire across the contacts of switch No. 1.

3. Perform the following procedure to test the circuit of mode selector switch No. 2. Place a jumper wire across the contacts of switch No. 2.

4. Turn the keyswitch to the ON position. Monitor the status screen on the electronic service tool. Connect the jumper wire and then disconnect the jumper wire.

Expected Result:

When the jumper wire is connected the switch should be in the CLOSED position.

Results:

• OK -

  Repair: Verify that the jumper wire has been removed. The suspect mode selector switch is faulty. Replace the switch and verify that the repair has eliminated the fault.

  STOP

• Not OK - Proceed to Test Step 4.

Test Step 4. Measure the Resistance of the Wire Harness at the ECM

1. Turn the keyswitch to the OFF position.

2. Disconnect P1 from J1.

3. Measure the resistance between P1:35 switch return and the following ECM pins:
   • P1:46Mode Switch No. 2

   • P1:39 Mode Switch No. 1

4. Cycle each mode switch to the OFF position and to the ON position.

Expected Result:

The resistance is less than 10 Ohms in the mode switch ON position.

The resistance is more than 4000 Ohms in the mode switch OFF position.

Results:

• OK - There is no faults in the harness. Proceed to Test Step 5.

• Not OK - The fault is in the harness between the sensor connector and the P1 connector.

  Repair: Repair the connector or replace the connector.Use the electronic service tool in order to clear all logged diagnostic codes and then verify that the repair has eliminated the fault.

  Proceed to Test Step 5 if the fault has not been eliminated.

Test Step 5. Test the ECM

1. Turn the keyswitch to the OFF position.

2. Temporarily disconnect the P1 connector from the ECM. Remove the pins 35, 39 and 46 from the P1 connector.

3. Reconnect the P1 connector.

4. Turn the keyswitch to the ON position. Monitor the status screen of the electronic service tool.

5. Turn the keyswitch to the OFF position.

6. Disconnect the P1 from J1.

7. Insert a jumper wire between the suspect switch socket and P1:35.

8. Turn the keyswitch to the ON position. Monitor the status screen of the electronic service tool.

9. Turn the keyswitch to the OFF position.

Expected Result:

When the connections are removed from the P1 connector, the mode switch indication on the electronic service tool will be in the OFF position. The switch will indicate an open condition.

When the jumper is connected to the P1 connector, the mode switch indication on the electronic service tool will be in the ON position. The switch will indicate a closed condition.

Results:

• OK - The ECM is operating correctly.STOP

• Not OK - The fault has not been eliminated.

  Repair: Perform the following repair:

  1. Make sure that the latest flash file for the application is installed in the ECM. Refer to Troubleshooting, "Flash Programming".

  2. Contact the Technical Communicator.

     Note: This consultation can greatly reduce the repair time.

  3. If the Technical Communicator recommends the use of a test ECM, install a test ECM. Refer to Troubleshooting, "Replacing the ECM".

  4. Use the electronic service tool to recheck the system for active diagnostic codes.

  5. If the fault is resolved with the test ECM, reconnect the suspect ECM.

  6. If the fault returns with the suspect ECM, replace the ECM.

  7. Use the electronic service tool in order to clear all logged diagnostic codes and then verify that the repair eliminates the fault.

  STOP