LOCK 4D6069 - Caterpillar

Use this procedure in order to troubleshoot a high aftercooler coolant temperature or use this procedure if one of the following event codes is active. Refer to Troubleshooting, "Event Codes" for information about event codes.
Table 1
Event Code
Code and Description Conditions which Generate this Code System Response
E771(1) High Aftercooler Temperature The aftercooler coolant temperature is above the trip point pressure for the programmed delay time. The code is logged.
E771(2) High Aftercooler Temperature The code is logged.
The engine is derated.
E771(3) High Aftercooler Temperature The code is logged.
The engine is shut down. If the engine is shut down due to a high aftercooler temperature, the power to the engine ECM must be cycled in order to restart the engine.Probable Causes
Diagnostic codes and event codes
Low coolant level for the Separate Circuit Aftercooler system (SCAC)
SCAC Radiator
Leakage in the SCAC system
Damage to the piping for the SCAC system
Cooling fan for the SCAC system
Pressure cap for the radiator
SCAC water pump
Engine loadRecommended Actions
Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect Caterpillar Electronic Technician (ET) to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools", if necessary.
B. Download the "Product Status Report" from the engine ECM before performing any troubleshooting or clearing diagnostic trouble codes.
C. Determine if the diagnostic trouble code that directed to this procedure is present.
D. Look for active diagnostic codes that are associated with the system for the event code that directed to this procedure.
E771
Result: An associated code is present.
Repair: Troubleshoot any associated codes before continuing with this test.
Result: An E771 code is present.
Proceed to the next step.
Result: No active codes
STOP
2. Check for Low Coolant Level for the Separate Circuit Aftercooler System (SCAC)
A. Inspect the coolant level.
Coolant level
Result: The coolant level is OK.
Proceed to the next step.
Result: The coolant level is NOT OK.
Repair: Add coolant.
If the problem is not resolved, proceed to the next step.
3. SCAC Radiator
A. Check the cooling fins on the radiator for dirt and/or for debris.
B. Check the cooling fins on the radiator for damage.
C. Check the radiator for internal blockage. Check the temperature difference between the inlet and the outlet of the radiator.
Radiator
Result: The cooling fins are clean.
Continue with this step.
Result: The cooling fins are not clean.
Repair: Remove dirt and/or debris.
Result: The cooling fins are damaged.
Repair: Refer to the Systems Operation/Testing and Adjusting manual for instructions for testing and inspecting the cooling system.
Result: The cooling fins are not damaged.
Continue with this step.
Result: The scac radiator has an internal blockage.
Repair: Clean the scac radiator or perform the necessary repairs.
Result: The scac radiator does not have an internal blockage
If the problem is not resolved, proceed to the next step.
4. Look for SCAC System Leakage
A. Check the cooling system for leaks.
1. Inspect the coolant for presence of bubbles.
Note: Cavitation will reduce the efficiency of the cooling system.
Leak
Result: The cooling system is OK.
Proceed to the next step.
Result: The cooling system is NOT OK.
Repair: Repair the cooling system.
If the problem is not resolved, proceed to the next step.
5. Look for Damage to the Piping for the SCAC System
Note: Damaged piping can restrict