PIN 2707973 - Caterpillar

The Electronic Control Module (ECM) detects an abnormal difference in pressure between the atmospheric pressure and the turbocharger inlet pressure. Information on default settings and ranges for these event codes can be found in Troubleshooting, "Event Codes".System Response:The 172-1 event code will be logged.The 172-2 event code will be logged.Possible Performance Effect:172-1None172-2The engine power will be derated.Troubleshooting:There may be a problem with the air cleaner.Test Step 1. Check the Air FiltersClean plugged air filters or replace plugged air filters. Refer to the Operation and Maintenance Manual. Ensure that the repair eliminates the problem.Results:
OK - STOP
Not OK - Proceed to Test Step 2.Test Step 2. Inspect the Sensors, the Wiring, and the Electrical ConnectorsInspect the atmospheric pressure sensor and the turbocharger inlet pressure sensor for proper installation.Inspect all of the wiring and the connectors that are associated with the sensors. Refer to the engine's Electrical Schematic and refer to Troubleshooting, "Electrical Connectors - Inspect". Ensure that all of the wiring and the connectors are in good condition.Expected Result:The sensors are properly installed. All connectors, pins, and sockets are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion, and of pinch points.Results:
OK - The sensors, the wiring, and the connectors are OK. Proceed to Test Step 3.
Not OK - There is a problem with a sensor, with the wiring, or with a connector.Repair: Make the necessary corrections. Replace parts, if necessary. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.STOPTest Step 3. Check for Active Diagnostic Codes
Connect the Caterpillar Electronic Technician (ET) to the service tool connector.
Turn ON the power to the ECM but do not start the engine.
Check for active diagnostic codes that are related to the atmospheric pressure sensor and/or to the turbocharger inlet pressure sensor. Expected Result:There are no active diagnostic codes that are related to the atmospheric pressure sensor or to the turbocharger inlet pressure sensor.Results:
OK - There are no active diagnostic codes that are related to the atmospheric pressure sensor or to the turbocharger inlet pressure sensor. Proceed to Test Step 4.
Not OK - There is at least one active diagnostic code that is related to the atmospheric pressure sensor or to the turbocharger inlet pressure sensor.Repair: Troubleshoot the active diagnostic code before continuing with this procedure.STOPTest Step 4. Monitor the Air Filter Restriction with the Engine Stopped
Verify that the power to the ECM is ON with the engine