SEAL 8J0393 - Caterpillar

The Engine Control Module (ECM) monitors the intake manifold air for excessive temperature. The following events are associated with high intake manifold air temperature:
Table 1
Codes for High Intake Manifold Air Temperature    
J1939 Code    Description    Information    
105-15     Engine Intake Manifold 1 Temperature : High - Least Severe (1)     The coolant temperature is above
99 °C (210 °F). The intake manifold air temperature exceeds
90 °C (194 °F) for four seconds. A snapshot is taken. The code is logged.    
105-16     Engine Intake Manifold 1 Temperature : High - Moderate Severity (2)     The coolant temperature is above
99 °C (210 °F). The intake manifold air temperature exceeds
110 °C (230 °F) for four seconds. A snapshot is taken. The code is logged.    Use this procedure to determine the cause of high intake manifold air temperature.
Verify that the coolant is filled to the proper level. If the coolant level is too low, air will get into the cooling system. Air in the cooling system will cause a reduction in coolant flow. Coolant flow is required in order to cool the intake air.
Check the aftercooler for debris or damage. Debris between the fins of the aftercooler core restricts air flow through the core.
Check the operation of the cooling fan. A fan that is not turning at the correct speed can cause improper air speed across the aftercooler core. The lack of proper air flow across the aftercooler core can cause the intake air not to cool to the proper temperature.
Check for a restriction in the air inlet system. A restriction of the air that is coming into the engine can cause high cylinder temperatures. High cylinder temperatures cause higher than normal temperatures in the cooling system. The coolant temperature must be within the correct range in order to cool the intake air.
Check for a restriction in the exhaust system. A restriction of the air that is coming out of the engine can cause high cylinder temperatures.
Consider high outside temperatures. When outside temperatures are too high for the rating of the cooling system, there is not enough of a temperature difference between the outside air and coolant temperatures.
Consider high altitude operation. The cooling capacity of the cooling system is reduced as the engine is operated at higher altitudes.
The engine may be running in the lug condition. When the load that is applied to the engine is too large, the engine will run in the lug condition. When the engine is running in the lug condition, engine rpm does not increase with an increase of fuel. This lower engine rpm causes a reduction in coolant flow through the system.