WRENCH--FRONT IDLER ADJUSTING 9F3869 - Caterpillar

Use this procedure in order to troubleshoot an occurrence of a high exhaust temperature.Certain operating conditions may cause the calculated exhaust temperature to increase to a level that may damage engine components. If a high exhaust temperature occurs, the Electronic Control Module (ECM) derates the engine in order to reduce the calculated exhaust temperature. The engine is derated only to a level that allows the calculated exhaust temperature to return to an acceptable level.Probable Causes
Air inlet and exhaust system
Engine operating conditions
Obstructed aftercooler
Separate Circuit Aftercooler (SCAC) temperature regulatorsRecommended Actions
Note: The procedures have been listed in order of probability. Complete the procedures in the order of the listed test steps.
Table 1
Troubleshooting Test Steps Values Results
1. Check the Air Inlet and Exhaust System for Problems
A. Check for an air filter restriction. Clean plugged air filters or replace plugged air filters.
B. Check the air inlet and exhaust system for restrictions and/or leaks.
C. Check the performance of the turbocharger. Ensure that recommended maintenance is performed on the turbocharger.
Air inlet and exhaust system
Result: The air filter, air inlet system, exhaust system, and turbocharger are in good repair.
Proceed to Test Step 3.
Result: The air filter is restricted, air inlet and/or exhaust system is restricted or leaking, or a problem with the turbocharger is found.
Repair: Repair or replace any necessary components.
Verify that the repair eliminated the problem.
2. Check the Engine Operating Conditions
A. Check the histogram to determine if the high exhaust temperature was due to normal operation.
When possible, interview the operator. Determine if the engine is being operated under heavy load. Ensure that the engine is being operated at the proper engine speed.
If derates are suspected, reset histogram and return the unit to service. If the histogram repopulates without fault codes, the engine was under normal operation.
Normal operation
Result: The code was logged during a heavy load.
Repair: Reduce the load on the engine.
Verify that the repair eliminated the problem.
Result: The code was not logged during a heavy load.
Proceed to Test Step 4.
3. Check for an Obstructed Aftercooler
A. The intake manifold air temperature can increase if the flow through the aftercooler is obstructed. Check the aftercooler for obstructions or debris. Ensure that the flow of air or coolant through the aftercooler is adequate.
Obstructed aftercooler
Result: The engine aftercooler was obstructed.
Repair: Clear any obstructions.
Verify that the repair eliminated the problem.
4. SCAC Temperature Regulators
A. Check the operation of the SCAC temperature regulators. Refer to Specifications, "Water Temperature Regulator" for additional information.
Temperature Regulators
Result: The SCAC temperature regulators operate correctly.
Result: There is a problem with the SCAC temperature regulators.
Repair: Replace the regulators.
Verify that the repair eliminated the problem.
If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).