0321723 JOHNSON HOSE,Cylinder head,port

The Engine Control Module (ECM) detects the following conditions:
The intake manifold air temperature is equal to 90 °C (194 °F) or above 90 °C (194 °F).
The engine coolant temperature is greater than 99 °C (210.2 °F).
The engine has been running for at least 30 seconds.Note: This diagnostic code represents a critical event. This diagnostic code does not represent an electronic system fault.System Response:The check engine lamp will flash.This diagnostic code requires a customer password in order to be cleared."DIAG" will be displayed next to the status for "Intake Manifold Air Temperature" on Caterpillar Electronic Technician (ET).Possible Performance Effect:The ECM does not derate the power. Also, the ECM does not limit the engine rpm or the vehicle speed due to this diagnostic code.Troubleshooting:This diagnostic code indicates an excessive temperature in the air intake manifold. This diagnostic code does not indicate a problem with the ECM or a problem with the temperature sensor for the air intake manifold.Test Step 1. Check for Diagnostic Codes.
Ensure that Cat ET is connected to the data link connector.
Turn the ignition key switch to the ON position. The engine should be off.
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.STOPTest Step 2. Inspect Electrical Connectors and Wiring.
Turn the ignition key switch to the OFF/RESET position.
Thoroughly inspect the following connectors:
J2/P2 ECM engine harness connector
J1/P1 ECM vehicle harness connector
Connector terminals for the sensorRefer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the inlet manifold temperature sensor.
Check the ECM connector (allen head screw) for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
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 are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion or of pinch points.Results:
OK - Proceed to Test Step 3.
Not OK - There is a problem with the wiring.Repair: 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.STOPTest Step 3. Check the Sensor in the Engine.
Ensure that the temperature of the engine is cool before starting this procedure.
Turn the ignition key switch to the ON position.
Note the temperature for the sensor on the status screen .
Start the engine but remain parked.
Monitor the intake manifold air temperature on the 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:
OK - 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
Not OK - Proceed to Test Step 4.Test Step 4. Compare the Temperature Reading to the Temperature from Another Gauge.
Turn the ignition key switch to the OFF/RESET position. The engine should be OFF.
Remove the temperature sensor from the engine.
Connect the sensor to the engine harness. Turn the ignition key switch to the ON position. 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.
The status screen will display the temperature reading from the sensor. Compare the temperature reading to the temperature reading from the 6V-9130 Temperature Adapter.
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:
OK - 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
Not OK - Repair: Perform the following diagnostic procedure:
Temporarily install another sensor.
Repeat this test step.
If the problem is resolved with the new sensor, replace the sensor.
Verify that the repair eliminates the problem. STOP