3126B and 3126E On-highway Engines Caterpillar

The Engine Control Module (ECM) detects the following conditions:

• The engine has been running for at least 30 seconds.

• The engine coolant temperature is above 99 °C (210 °F).

The inlet air temperature has risen to 110 °C (230 °F).

System Response:

The value of the "Engine Monitoring Mode" parameter will determine the actions that are taken by the ECM. The engine monitoring system can be programmed for the following actions: OFF, WARNING, DERATE and SHUTDOWN.

OFF - Engine performance will not be affected.

WARNING - Engine performance will not be affected.

DERATE - Engine speed is limited to a maximum of 1350 rpm. The vehicle speed is limited to a maximum of 72 km/h (45 mph), and the power is limited.

SHUTDOWN - The engine will shut down if the engine is derated for the specified period of time.

Refer to Troubleshooting, "Customer Configuration Parameters" for information that is related to monitoring system parameters.

The ECM logs the diagnostic code into permanent memory.

Note: This diagnostic code requires a customer password in order to be cleared.

Test Step 1. Check for Diagnostic Codes.

1. Connect ET to the cab data link connector.

2. Turn the keyswitch to the ON position. The engine should be off.

3. Check for any active diagnostic codes or logged diagnostic codes.

Expected Result:

There should be no diagnostic codes that are present.

Results:

• OK - Proceed to Test Step 2.

• Not OK -

  Repair: Repair the diagnostic codes that are present. For further details, refer to Troubleshooting, "Troubleshooting With a Diagnostic Code".Ensure that the repair eliminates the problem.

  STOP

Test Step 2. Inspect Electrical Connectors And Wiring.

1. Thoroughly inspect the following connectors:
   • J2/P2 ECM engine harness connector

   • J1/P1 ECM vehicle harness connector

   • connector terminals for the sensor

   Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.

2. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the appropriate diagnostic code.

3. Check the ECM connector (allen head screw) for the proper torque of 6.0 N·m (55 lb in).

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

Expected Result:

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

Choose the OK option in order to select the sensor that requires troubleshooting or select the NOT OK option if the wiring is causing the problem.

Results:

• OK - Proceed to Test Step 3.

• Not OK - Repair the connectors or wiring and/or replace the connectors or wiring. 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 3. Check the Sensor In The Engine.

1. Ensure that the temperature of the engine is cool before starting this procedure.

2. Connect ET to the cab data link connector.

3. Turn the ignition key switch to the ON position.

4. Note the temperature for the sensor on the ET status screen.

5. Start the engine but remain parked.

6. Monitor the temperature for the sensor on the ET status screen as the engine is warming.

Expected Result:

The temperature before starting the engine should be within reasonable limits, and the temperature increases as the engine warms.

Note: The engine may require several hours to cool down depending on the ambient air temperature around the vehicle.

Results:

• Yes - The sensor is functioning correctly. If a problem is still suspected the problem is a mechanical problem. The problem is not an electronic problem.

  Repair: Perform the following diagnostic procedure:Refer to Troubleshooting, "Troubleshooting without a Diagnostic Code" for a procedure that best describes the conditions.

  STOP

• No - Proceed to Test Step 4.

Test Step 4. Compare The Temperature Reading To The Temperature From Another Gauge.

1. Remove the temperature sensor from the engine.

2. Connect the sensor to the engine harness. Hold the sensor and the thermocouple probe from the 6V-9130 Temperature Adapter in the air. Allow three minutes for the sensor and the probe to respond to the temperature of the air.

3. The ET status screen will display the temperature reading from the sensor. Compare the temperature reading to the temperature reading from the 6V-9130 Temperature Adapter .

4. Hold the sensor and the thermocouple probe in your hand and check the temperatures again. Do not expose the sensor to a flame.

Expected Result:

The two measurements are within 15 °C (27 °F) of each other.

Note: Do not expect the sensor and the thermocouple probe from the 6V-9130 Temperature Adapter to respond to the temperature change at the same rate.

Results:

• Yes - The sensor is functioning correctly. If a problem is still suspected the problem is a mechanical problem. The problem is not an electronic problem.

  Repair: Perform the following diagnostic procedure:Refer to Troubleshooting, "Troubleshooting without a Diagnostic Code" for a procedure that best describes the conditions.

  STOP

• No -

  Repair: Perform the following diagnostic procedure:

  1. Temporarily install another sensor.

  2. Repeat this test step.

  3. If the problem is resolved with the new sensor, replace the sensor.

  4. Verify that the repair eliminates the problem.

  STOP