C6.6 Generator Set Caterpillar

Use this procedure if another procedure has directed you here. Use this procedure if the following diagnostic code is active:

• 1690-8 Analog Speed Demand Abnormal signal

The diagnostic code above relates to an analog voltage output from the system that is controlling the engine.

Note: In other applications, the analog voltage output is generated by an accelerator or a hand throttle. These terms will still be displayed on the electronic service tool for this application.

Use the electronic service tool in order to check the input status.

Illustration 1	g01810415
Schematic of the analog speed control device

Illustration 2	g01810453
Typical view of the pin locations on the P1connector for the speed control circuit (33) Device ground (GND) (54) Analog throttle input 1

Test Step 1. Check for Connector Damage

1. Turn the keyswitch to the OFF position.

2. Check the connectors and the harness for the following faults: damage, abrasion, corrosion and incorrect attachment.

3. Refer to Troubleshooting, "Electrical Connectors - Inspect".

4. Perform a 45 N (10 lb) pull test on each of the wires in the harness that are associated with the speed control device. Check the wire connectors at the ECM and at the control system. The wire connectors are shown in Figure 2.

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

Expected Result:

The connectors and the harness should be free of the following faults: damage, abrasion, corrosion and incorrect attachment.

Results:

• OK - Proceed to Test Step 2.

• Not OK -

  Repair: Repair the connectors or the harness and/or replace the connectors or the harness.Verify that the repair eliminates the fault.

  STOP

Test Step 2. Check for active Diagnostic Codes

1. Turn the keyswitch to the ON position.

2. Use the electronic service tool to check for diagnostic codes.

Expected Result:

RESULT 1 The electronic service tool displays the following active diagnostic code or the following recently logged diagnostic code:

• 1690-8

RESULT 2 The electronic service tool displays no active diagnostic codes:

Results:

• Result 1 - Proceed to Test Step 3.

• Result 2 - There may be an intermittent connection in the wiring. Proceed to Test Step 3.

Test Step 3. Check the Control Signal

1. Refer to the OEM supplied manual for the control system.

2. Check that the output signal from the control system is correct.

Expected Result:

The output signal from the control system should be within the specification in the OEM supplied manual.

Results:

• OK - The output signal from the control system is correct. Proceed to Test Step 4.

• Not OK - The output signal from the control system is not correct or the control system is incorrectly configured.

  Repair: Repair the control system or configure the control system. Refer to the OEM supplied manual.Verify that the repair eliminates the fault.

  STOP

Test Step 4. Check the Signal at the ECM

1. Turn the keyswitch to the OFF position.

2. Disconnect the P1 connector.

3. Temporarily remove the pin from P1:54.

4. Reconnect P1 connector.

5. Connect the red probe of a multimeter to the removed pin and the black probe of a multimeter to P1:33.

6. Turn the keyswitch to the ON position.

7. Check that the signal at the ECM is the same value as the output signal from the control system.

8. Turn the keyswitch to the OFF position.

9. Remove P1 connector and reinstall P1:54.

10. Reconnect P1 connector.

Expected Result:

The signal at the ECM is the same value as the output signal from the control system.

Results:

• OK - The ECM terminals have the correct voltage for the control system.

  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

• Not OK - There is a fault in the harness or the connectors between the sensor and the ECM. Check all of the connections between the ECM and the control system. Repair the damaged cables or replace the damaged cables. Check that the repairs have eliminated the fault.STOP