C7.1 Marine Engine Caterpillar

Intake Manifold Air Temperature Is High

Usage:

C7.1 JEZ

The Electronic Control Module (ECM) monitors the intake manifold air for excessive temperature. The following codes are associated with high intake manifold air temperature:

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Table 1
Diagnostic Codes for High Intake Manifold Air Temperature
J1939 Code	Code Description	Comments
105-15	Engine Intake Manifold #1 Temperature : High - least severe (1)	The engine has been running for 3 minutes. No other 105 codes are active. 168 codes are not active. The intake manifold air temperature exceeds the value that is programmed into the ECM for 8 seconds. The code is logged. This code will be reset when the temperature is less than 63° C (145° F) for 4 seconds.
105-16	Engine Intake Manifold #1 Temperature : High - Moderate Severity (2)	The engine has been running for 3 minutes. No other 105 codes are active. 168 codes are not active. The intake manifold air temperature exceeds the value that is programmed into the ECM for 8 seconds. The engine will be derated. The code is logged. This code will be reset when the temperature is less than 63° C (145° F) for 20 seconds.

Probable Causes

Coolant level
Cooling fan (if applicable)
Air inlet and exhaust system
Ambient temperature
Running condition

Recommended Actions

Note: The procedures have been listed in order of probability. Complete the procedures in order.

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Table 2
Troubleshooting Test Steps	Values	Results
1. Coolant Level A. Check that the coolant is filled to the correct level. Note: 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	Result: The coolant level is low. Fill the coolant system to the correct level. Refer to the Operation and Maintenance Manual, "Coolant Level - Check". Result: The coolant level is OK. Proceed to Test Step 2.
2. Air Intake and Exhaust System A. Check the air intake and exhaust system for the following defects: -Blockages -Restrictions -Damage to the air intake ducts and hoses -Loose connections and air leaks	Air intake and exhaust	Result: The air intake or exhaust system is blocked, restricted, damaged, or loose. Make all necessary repairs to the air intake system. Result: The air intake and exhaust system is OK. For applications with a raw water cooling system or a keel cooled cooling system, proceed to Test Step 3. For applications with a radiator cooling system, proceed to Test Step 5.
3. Check for an Obstructed Heat Exchanger A. The intake manifold air temperature can increase if the flow through the heat exchanger is obstructed. Check the heat exchanger for obstructions or debris. Ensure that the flow of coolant through the heat exchanger is adequate.	Obstructed heat exchanger	Result: The heat exchanger was obstructed. Clear any obstructions. Return the unit to service. Result: The heat exchanger was not obstructed. Proceed to Test Step 4.
4. Check the Flow Through the Sea Water Pump A. The intake manifold air temperature can increase if the flow from the sea water pump is reduced. Ensure that the flow of water through the sea water pump is adequate.	Obstructed sea water pump	Result: The sea water pump is obstructed. Clear any obstructions. Return the unit to service. Result: The flow from the sea water pump is reduced. Repair the sea water pump or replace the sea water pump. Result: The output from the sea water pump is sufficient. Contact the Technical Communicator at a Cat dealer.
5. Check for an Obstructed CAC A. The intake manifold air temperature can increase if the flow through the CAC is obstructed. Check the CAC for obstructions or debris. Ensure that the flow of air through the CAC is adequate.	Obstructed heat exchanger	Result: The CAC was obstructed. Clear any obstructions. Return the unit to service. Result: The CAC was not obstructed. Proceed to Test Step 6.
6. Ambient Temperature A. Check for a high ambient temperature. Note: When outside temperatures are too high, there is insufficient temperature difference between the outside air and the intake air.	Ambient Temperature	Result: The ambient air temperature is high. Operate the engine at reduced speed or reduced power. Result: The ambient air temperature is OK. Proceed to Test Step 7.
7. Running Condition A. Check that the engine is not operating in the lug condition. Note: 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.	Running condition	Result: The engine is operating in the lug condition. Reduce the load on the engine or, if possible, increase the power rating of the engine. 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).