C18 Marine Generator Set Engines Caterpillar

Use this procedure to troubleshoot any suspect problems with the following sensors:

• Primary engine speed/timing sensor

• Secondary engine speed/timing sensor

This procedure covers the following diagnostic codes:

• 320-02 Speed/Timing Sensor Loss of Signal

• 320-11 Speed/Timing Sensor mechanical failure

• 342-02 Loss of Secondary Engine Speed signal

• 342-11 Secondary Engine Speed Sensor mechanical failure

The engine uses two engine speed/timing sensors:

Primary engine speed/timing sensor - The primary engine speed/timing sensor detects the reference for engine speed and timing from a timing ring with a notched pattern that has been machined onto a portion of the crankshaft gear.

Secondary engine speed/timing sensor - The secondary engine speed/timing sensor detects the reference for engine speed and timing from a timing ring with a notched pattern that has been machined onto a portion of the camshaft gear.

Each of the engine speed/timing sensors produces a signal as the respective timing ring rotates past the tip of the sensor. The Electronic Control Module (ECM) uses these signals to determine the engine speed and the engine timing.

When the timing has been determined, the ECM triggers each injector in the correct firing order at the correct time. The actual timing and duration of each injection is based on engine rpm, load, and demand.

If the engine is running and the signal from one sensor is lost, no noticeable change in engine performance will be noticed. If the engine is running and the signals from both sensors are lost, fuel injection will be terminated and the engine will be shut down by the ECM.

The engine will start when only one sensor signal is present. The engine will not start if the signals from both sensors are lost.

Both sensors are magnetic sensors. The two sensors are not interchangeable. Do not switch the positions of the sensors. The two sensors must be replaced as a pair. If the sensors are replaced, a timing calibration is not necessary for the engine.

If a replacement of the ECM is required, the ECM parameters and the timing calibration can be transferred from the suspect ECM to the replacement ECM. Timing calibration will not be necessary. This feature requires the Caterpillar Electronic Technician (ET) and this feature is only possible if the existing ECM can communicate with Cat ET. Use the "Copy Configuration - ECM Replacement" feature on Cat ET.

When the sensors are being installed, complete all of the following tasks:

• Lubricate the O-ring with oil.

• Ensure that the sensor has a face 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 on both sides.

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

Illustration 1	g01150285
Schematic for the engine speed/timing circuit

Test Step 1. Check for Diagnostic Codes

1. Connect Cat ET to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools".

2. Turn the keyswitch to the ON position.

3. Start the engine and run the engine until the engine is at the normal operating temperature.

   Note: If the engine will not start, monitor the engine rpm on Cat ET while the engine is being cranked. Cat ET may need to be powered from another battery while the engine is being cranked.

4. Check for the following diagnostic codes:

   • 190-02

   • 190-11

   • 342-02

   • 342-11

   Note: If the diagnostic code is logged but not active, run the engine until the engine is at normal operating temperature. The problem may only occur when the engine is at the normal operating temperature. If the engine will not start, monitor the engine rpm on the electronic service tool while the engine is being cranked. The electronic service tool may need to be powered from another battery while the engine is being cranked. This is done so the electronic service tool will not reset.

Expected Result:

One or both of the diagnostic codes that are listed above are logged or active.

Note: If the engine will not start and Cat ET displayed 0 rpm during cranking, select "No Engine rpm".

Results:

• No Engine rpm - Engine rpm is not indicated on Cat ET. Proceed to Test Step 2.

• Active Code - There is an active diagnostic code or a logged diagnostic code for an engine speed/timing sensor. Proceed to Test Step 4.

• No Codes - None of the codes that are listed are active or logged.

  Repair: Refer to the appropriate symptoms in Troubleshooting, "Troubleshooting Without a Diagnostic Code".

  STOP

Test Step 2. Check the Installation of the Sensors and the Bracket

Illustration 2	g01176097
Typical engine speed/timing sensor (1) Mounting flange (2) Mounting surface

1. Visually inspect each sensor assembly without removing the sensor assembly from the engine. Ensure that flange (1) is installed squarely against surface (2).

   Remove the suspect sensor assembly from the engine.

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   Illustration 3	g01167704
   Typical engine speed/timing sensor (3) O-ring

2. Ensure that one O-ring (3) is installed on the sensor. Check the O-ring for damage. Replace the O-ring, if necessary.

Results:

• OK - The sensor's components are OK.

  Repair: Perform the following procedure in order to properly install the sensor assembly:

  1. Lubricate the O-ring with engine oil.

  2. Fully seat the sensor assembly in the engine.

     Note: If the sensor assembly will not fully seat into the engine, replace the sensor assembly.

  3. Tighten the bracket bolt.

  4. Connect the sensor's electrical connectors. Verify that the connectors are latched on both sides.

  5. Ensure that the harness is properly secured, and that the tie-wraps are placed in the correct location.

  Proceed to Test Step 4.

• Not OK - At least one of the sensor assembly's components is not OK.

  Repair: Obtain a new sensor assembly. Perform the following procedure in order to properly install the sensor assembly:

  1. Lubricate each O-ring with engine oil.

  2. Fully seat the sensor assembly in the engine.

     Note: If the sensor assembly will not fully seat into the engine, replace the sensor assembly.

  3. Tighten the bracket bolt.

  4. Connect the sensor's electrical connectors. Verify that the connector is latched.

  5. Ensure that the harness is properly secured, and that the tie-wraps are placed in the correct location.
  Verify that the problem is resolved.

  STOP

Test Step 3. Inspect the Electrical Connectors and the Wiring

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Illustration 4	g01175131
Engine components for the engine speed/timing sensors (4) J402/P402 connectors for the secondary engine speed/timing sensor (5) J401/P401 connectors for the primary engine speed/timing sensor (6) J2/P2 ECM connector

1. Thoroughly inspect connectors (4), (5), and (6). Refer to Troubleshooting, "Electrical Connectors - Inspect".
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   Illustration 5	g01175138
   P2 terminals that are associated with the engine speed/timing sensors (P2-48) Primary engine speed/timing − (P2-49) Primary engine speed/timing + (P2-58) Secondary engine speed/timing + (P2-59) Secondary engine speed/timing −

2. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the engine speed/timing sensors.

3. Check the allen head screw on each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.

4. Check the harness and the wiring for abrasion and for pinch points from each sensor back to the ECM.

Expected Result:

All of the connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion, and of pinch points.

Results:

• OK - The harness and connectors appear to be OK. Proceed to Test Step 4.

• Not OK - The connectors and/or wiring are not OK.

  Repair: Repair the wiring and/or the connectors. Replace parts, if necessary. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled. Verify that the repair eliminates the problem.

  STOP

Test Step 4. Measure the Sensor Resistance Through the Engine Harness

1. Turn the keyswitch to the OFF position.

2. Disconnect the P2 connector at the ECM.

3. If you are troubleshooting a problem with the primary engine speed/timing sensor, perform the following procedure:

   1. Measure the sensor's resistance between P2-48 (primary engine speed/timing +) and P2-49 (primary engine speed/timing -).

      Resistance ... 110 to 200 Ohms

4. If you are troubleshooting a problem with the secondary engine speed/timing sensor, perform the following procedure:

   1. Measure the sensor's resistance between P2-58 (secondary engine speed/timing +) and P2-59 (secondary engine speed/timing -).

      Resistance ... 1000 to 1200 Ohms

Expected Result:

The resistance measurements are within the specifications.

Results:

• OK - The resistance measurements are within the specifications. The wiring appears to be OK. There could be a problem with the sensor or with the ECM. Proceed to Test Step 6.

• Not OK - At least one of the resistance measurements is not within the specifications. Proceed to Test Step 5.

Test Step 5. Measure the Sensor Resistance at the Sensor Connector

1. Disconnect the engine harness from the suspect sensor.

2. For the primary engine speed/timing sensor, measure the resistance between J401-2 (primary engine speed/timing +) to J401-1 (primary engine speed/timing −).

   Resistance ... 110 to 200 Ohms

3. For the secondary engine speed/timing sensor, measure the resistance between J402-2 (secondary engine speed/timing +) to J402-1 (secondary engine speed/timing −).

   Resistance ... 1000 to 1200 Ohms

Expected Result:

The resistance measurement for the suspect sensor is within the specification.

Results:

• OK - The resistance measurement for the suspect sensor is within the specification. The sensor's resistance measurement at the P2 connector was incorrect. There is a problem with the wiring. There may be a problem with a connector.

  Repair: Repair the connection and/or the wiring, when possible. Replace parts, if necessary. Twisted pair wiring is required. The wiring must have at least one twist per inch. Verify that the problem is resolved.

  STOP

• Not OK - The resistance measurement for the suspect sensor is not within the specification. There is a problem with the sensor. Proceed to Test Step 6.

Test Step 6. Check the Sensor

1. Temporarily replace the suspect sensor. Perform the following procedure in order to replace the sensor assembly.

   Note: Do not switch the positions of the sensors. The sensors are not interchangeable. A timing calibration is not required when the sensors are replaced.

   1. Lubricate the O-ring seals with oil.

   2. Fully seat the sensor into the front housing.

   3. Tighten the bracket bolt.

   4. Connect each connector and verify that the latch tab of each connector is latched on both sides.

   5. Ensure that the harness is properly secured, and ensure that the harness is attached to the harness clip.

2. Reconnect all of the connectors.

3. Clear any diagnostic codes.

4. Start the engine. Run the engine until the engine is at normal operating temperature. The problem may only occur when the engine is at the normal operating temperature.

Expected Result:

No diagnostic codes for the engine speed/timing sensor are activated.

Results:

• OK - No diagnostic codes for the engine speed/timing sensor are activated. Resume normal operation.

  STOP

• Not OK - The diagnostic code for the engine speed/timing sensor remains. Replacing the sensor did not solve the problem. There may be a problem with the ECM.

  Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this procedure again. If the problem is not resolved, install a new ECM. Refer to Troubleshooting, "Replacing the ECM". Verify that the original problem is resolved.

  STOP