C6.6 Generator Set Caterpillar

Use this procedure to troubleshoot the system under the following conditions:

• Use this procedure if another procedure has directed you here.

• There is an active diagnostic code or a recently logged diagnostic code that is related to the following:

• 190-8 Engine Speed signal abnormal

• 342-8 Secondary Engine Speed signal abnormal

The engine uses two engine speed/timing sensors. The primary speed/timing sensor is located on the left hand side of the cylinder block close to the flywheel housing. The secondary speed/timing sensor is mounted on the fuel rail pump. The primary speed/timing sensor that is mounted on the cylinder block generates a signal by detecting the movement of the teeth that are located on the crankshaft timing ring. The crankshaft timing ring is connected to the crankshaft. The signal that is generated by the speed/timing sensor is transmitted to the Electronic Control Module (ECM). The ECM uses the signal from the speed/timing sensor to calculate the position of the crankshaft. To determine the engine speed, the ECM measures the time between the pulses that are created by the sensor as the crankshaft timing ring rotates.

The secondary speed/timing sensor generates a signal that is related to the camshaft position. The fuel rail pump is mechanically connected to the camshaft. The secondary speed/timing sensor detects the movement of the teeth on the timing ring in the fuel rail pump. The signal that is generated by the speed/timing sensor is transmitted to the ECM. The ECM calculates the speed and the rotational position of the engine by using the signal. During normal operation, the secondary speed/timing sensor is used to determine the timing for starting purposes.

During normal operation, the secondary speed/timing sensor is used to determine when the number 1 piston is at the top of the compression stroke for starting purposes. When the timing has been established, the primary speed/timing sensor is then used to determine the engine speed.

The loss of signal to the primary sensor and/or the secondary sensor will result in one of the following faults:

• The loss of signal from the secondary speed/timing sensor during start-up will prevent the engine from starting.

• The engine will continue to run when only one sensor signal is present from either the primary sensor or the secondary sensor.

• The loss of signal from the primary speed/timing sensor during operation of the engine will result in engine operation in the derate mode.

• Loss of signal from the primary sensor and the secondary sensor during operation of the engine will cause fuel injection to be terminated and the engine will stop.

The primary sensor and the secondary sensor are interchangeable components. If a sensor is suspect the sensors can be exchanged in order to eliminate a fault. If a secondary sensor is suspect and a replacement secondary sensor is not available, then the primary sensor and the secondary sensor can be exchanged. This will allow testing to determine if the secondary sensor is faulty.

Illustration 1	g01803493
The schematic for the speed/timing sensors

Illustration 2	g01803494
Typical view of the pin locations for the speed/timing sensors (10) Speed/ Timing sensor supply (8 Volts DC) (52) Primary speed timing sensor signal (53) Secondary speed sensor signal

Illustration 3	g01803515
Typical view of the sensor locations (1) Primary crankshaft speed/timing sensor (2) Secondary speed/timing sensor

Illustration 4	g01803516
(1) Primary speed/timing sensor (crankshaft) (2) Secondary speed/timing sensor (camshaft)

Illustration 5	g01212995
Typical example of the speed/timing sensor (1) Voltage Supply (8 Volts DC) (2) Signal (Sig)

Test Step 1. Inspect the Electrical Connectors and the Harness

1. Turn the keyswitch to the OFF position.

2. Thoroughly inspect the P2 connector and the suspect sensor connections. Refer to Troubleshooting, "Electrical Connectors - Inspect".

3. Perform a 45 N (10 lb) pull test on each of the wires in the suspect sensor connector and the sensor connections at the ECM. The wire connectors are shown in illustration 2.

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

5. Check the harness for abrasion and pinch points from the suspect sensor to the ECM.

6. Check that the suspect sensor is installed correctly. Check that the suspect sensor is fully seated into the engine. Check that the sensor is securely latched.

Expected Result:

The electrical connectors and the cables are correctly installed.

Results:

• OK - The harness is OK. Proceed to Test Step 2.

• Not OK -

  Repair: Repair the faulty connectors or the harness and/or replace the faulty connectors or the harness. Ensure that all of the seals are correctly in place and ensure that the connectors are correctly coupled.If a sensor must be replaced or the sensor must be reinstalled, complete all of the following tasks:

  • Lubricate the O ring with clean engine lubricating oil.

  • Ensure that the plug for the sensor has a seal inside the connector body. If a seal is damaged or missing, replace the seal.

  • Ensure that the sensor is fully seated into the engine before tightening the bracket bolt.

  • Ensure that the connector is latched.

  • Ensure that the harness is correctly secured, and ensure that the harness is attached to the harness clip.

  Verify that the repair has eliminated the fault.

  STOP

Test Step 2. Check for Active Diagnostic Codes and then Check for Recently Logged Diagnostic Codes

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. If the engine will start, then run the engine.

4. Use the electronic service tool in order to monitor active diagnostic codes or recently logged diagnostic codes.

Expected Result:

One or more of the following diagnostic codes are active or recently logged:

• 190-8 Engine Speed signal abnormal

• 342-8 Secondary Engine Speed signal abnormal

Results:

• 190-8 - Proceed to Test Step 4.

• 342-8 - Proceed to Test Step 3.

• Not OK - No active diagnostic codes or recently logged diagnostic codes are displayed.STOP

Test Step 3. Check the Harness Between the Secondary Speed/Timing Sensor and the ECM

1. Turn the keyswitch to the OFF position.

2. Disconnect the P2 connector. Disconnect the connector for the primary speed/timing sensor. Disconnect the connector for the secondary speed/timing sensor.

3. Check the resistance between P2:53 and terminal 2 on the secondary speed/timing sensor. The resistance should be less than 2.0 Ohms.

4. Check the resistance between P2:10 and terminal 1 on the secondary speed/timing sensor. The resistance should be less than 2.0 Ohms.

Expected Result:

The readings agree with the values that are listed above.

Results:

• OK - The harness is not OPEN circuit. Proceed to Test Step 5.

• Not OK - The harness or the connector is an open circuit or high resistance.

  Repair: Repair the faulty connectors or the harness. Replace the faulty connectors or the harness. Reconnect all sensor and ECM connectors. Ensure that all of the seals are correctly in place. Ensure that all connectors are correctly coupled.Verify that the repair has eliminated the fault.

  STOP

Test Step 4. Check the Harness Between the Primary Speed/Timing Sensor and the ECM.

1. Turn the keyswitch to the OFF position.

2. Disconnect the P2 connector. Disconnect the connector for the primary speed/timing sensor. Disconnect the connector for the secondary speed/timing sensor.

3. Check the resistance between P2:52 and terminal 2 on the secondary speed/timing sensor. The resistance should be less than 2.0 Ohms.

4. Check the resistance between P2:10 and terminal 1 on the secondary speed/timing sensor. The resistance should be less than 2.0 Ohms.

Expected Result:

The readings agree with the values that are listed above.

Results:

• OK - The harness is not OPEN circuit. Proceed to Test Step 6.

• Not OK - The harness is OPEN circuit.

  Repair: Repair the faulty connectors or the harness and/or replace the faulty connectors or the harness. Reconnect all sensor and ECM connectors. Ensure that all of the seals are correctly in place. Ensure that all connectors are correctly coupled.Verify that the repair eliminates the fault.

  STOP

Test Step 5. Check that the Connections and the Wiring to the Secondary Speed/Timing Sensor and the ECM are Isolated from Other Power Sources

1. Turn the keyswitch to the OFF position.

2. Disconnect the P2 connector. Disconnect the connector for the primary speed/timing sensor. Disconnect the connector for the secondary speed/timing sensor.

3. Measure the resistance from P2:53 (secondary speed/timing sensor signal input) to all other pins on the P2. Measure the resistance from P2:53 (secondary speed/timing sensor signal input) to the ground and battery+ terminals. The resistance should be more than 20,000 Ohms.

4. Measure the resistance from P2:10 speed/timing sensor (+8 Volt DC supply) to all other pins on the P2. Measure the resistance from P2:10 speed/timing sensor (+8 Volt DC supply) to the ground and the battery+ terminals. The resistance should be more than 20,000 Ohms.

Expected Result:

The readings agree with the values that are listed above.

Results:

• OK - There is no short circuit. Proceed to Test Step 7.

• Not OK - The harness has a short circuit.

  Repair: Repair the faulty connectors or replace the faulty connectors. Repair the faulty harness or replace the faulty harness. Reconnect all sensor and ECM connectors. Ensure that all of the seals are correctly in place. Ensure that all connectors are correctly coupled.Verify that the repair eliminates the fault.

  STOP

Test Step 6. Check that the Connections and the Wiring to the Primary Speed/Timing Sensor and the ECM are Isolated from the Other Power Sources

1. Turn the keyswitch to the OFF position.

2. Disconnect the P2 connector. Disconnect the connector for the primary speed/timing sensor. Disconnect the connector for the secondary speed/timing sensor.

3. Check the resistance between P2:52 to each of the other pins on P2. Check the resistance between P2:52 to the ground and battery+ terminals. The resistance should be more than 20,000 Ohms.

4. Check the resistance between P2:10 to each of the other pins on P2. Check the resistance between P2:10 to the ground and battery+ terminals. The resistance should be more than 20,000 Ohms.

Expected Result:

The readings agree with the values that are listed above.

Results:

• OK - The wires are not a short circuit. Proceed to Test Step 7.

• Not OK - The sensor wiring has a short circuit.

  Repair: Repair the faulty connectors or replace the faulty connectors. Repair the faulty harness or replace the faulty harness. Reconnect all sensor and ECM connectors. Ensure that all of the seals are correctly in place. Ensure that all connectors are correctly coupled.Verify that the repair eliminates the fault.

  STOP

Test Step 7. Check if a Replacement Sensor Eliminates the Fault

1. Turn the keyswitch to the OFF position.

2. Disconnect the suspect sensor and remove the suspect sensor from the engine.

3. Install a replacement sensor. Complete all of the following tasks:
   • Lubricate the O ring with clean engine lubricating oil.

   • Ensure that the plug for the sensor has a seal inside the connector body. If a seal is damaged or missing, replace the seal.

   • Ensure that the sensor is fully seated into the engine before tightening the bracket bolt.

   • Ensure that the connector is latched.

   • Ensure that the harness is correctly secured, and ensure that the harness is attached to the harness clip.

4. Turn the keyswitch to the ON position.

5. Start the engine.

6. Use the electronic service tool in order to monitor the diagnostic codes.

7. Verify that the replacement sensor has eliminated the fault.

Expected Result:

The fault has been rectified.

Results:

• OK - If the fault is eliminated with the replacement sensor, reconnect the suspect sensor. If the fault returns with the suspect sensor, install the replacement sensor.

  Repair: Verify that the repair eliminates the fault.

  STOP

• Not OK - The fault still exists. Proceed to Test Step 8.

Test Step 8. Check if the Replacement of the ECM Eliminates the Fault

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. Connect the electronic service tool to the diagnostic connector.

5. Turn the keyswitch to the ON position.

6. Start the engine.

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

Expected Result:

The fault is eliminated.

Results:

• OK -

  Repair: If the fault is eliminated with the test ECM, perform the following procedure:

  1. Reconnect the suspect ECM.

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

  3. 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 - The fault was not eliminated with a test ECM.

  Repair: Install the original ECM.

  1. If the fault persists, the fault may be a damaged timing ring. Check the timing ring and/or replace the timing ring.

  2. If the fault is not eliminated, repeat the diagnostic procedure from Step 1.

  STOP