C1.5 and C2.2 Engines for Caterpillar Built Machines Caterpillar

Exhaust Temperature Is High

Usage:

The Engine Control Module (ECM) monitors the following exhaust gas parameters:

Diesel Oxidation Catalyst (DOC) intake temperature
Diesel Particulate Filter (DPF) intake temperature
Diesel Particulate Filter (DPF) outlet temperature

Certain operating conditions can cause the exhaust temperature to increase to a level that may damage engine components. If a high exhaust temperature occurs, the ECM derates the engine in order to reduce the exhaust temperature. The engine is derated only to a level that allows the exhaust temperature to return to an acceptable level. If the exhaust temperature continues to increase, the engine may be shut down.

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Table 1
Diagnostic Trouble Codes
J1939 Code	Description	Comments
3241-15	Exhaust Gas Temperature 1 : High - least severe (1)	The DPF outlet temperature has exceeded 700° C (1292° F). Engine speed is derated to 1800 rpm. Engine load is derated to 50%.
3241-16	Exhaust Gas Temperature 1 : High - moderate severity (2)	The DPF outlet temperature has exceeded 800° C (1472° F). Engine speed may be shut down.
3242-15	Aftertreatment #1 DPF Intake Gas Temperature : High - least severe (1)	The DPF intake temperature has exceeded 700° C (1292° F). Engine speed is derated to 1800 rpm. Engine load is derated to 50%.
3242-16	Aftertreatment #1 DPF Intake Gas Temperature : High - moderate severity (2)	The DPF intake temperature has exceeded 800° C (1472° F). Engine speed may be shut down.
4765-15	Aftertreatment #1 Diesel Oxidation Catalyst Intake Gas Temperature : High - least severe (1)	The DOC intake temperature has exceeded 700° C (1292° F). Engine speed is derated to 1800 rpm. Engine load is derated to 50%.
4765-16	Aftertreatment #1 Diesel Oxidation Catalyst Intake Gas Temperature : High - moderate severity (2)	The DOC intake temperature has exceeded 800° C (1472° F). Engine speed may be shut down.

Probable Causes

Diagnostic codes
Intake air leak
Exhaust system restriction
Engine operating conditions
High altitude

Complete the procedure in the order in which the steps are listed.

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Table 2
Troubleshooting Test Steps	Values	Results
1. Check for Diagnostic Codes A. Establish communication between the electronic service tool and the ECM . Refer to Troubleshooting, "Electronic Service Tools", if necessary. B. Determine if a code is active or logged.	Diagnostic codes	Result: A diagnostic code is active or logged. Troubleshoot the diagnostic code. Refer to Troubleshooting, "Diagnostic Trouble Codes" . Result: A diagnostic code is not active or logged. Proceed to Test Step 2.
2. Check for Intake Air Leaks A. Apply a light load to the engine and check for intake air leakage.	Intake air leaks	Result: An intake air leak was found. Repair the leak. Return the unit to service. Result: An intake air leak was not found. Proceed to Test Step 3.
3. Check for Restrictions in the Exhaust System A. Inspect the exhaust system from the exhaust manifold to the tail pipe for restrictions or damage. B. If necessary, inspect the DOC and DPF for blockages.	Exhaust system restrictions	Result: The exhaust system is restricted or damaged. Repair the faulty parts. Return the unit to service. Result: The DOC or the DPF are blocked. Investigate the cause of the blockage and clean or replace the blocked parts. Result: The exhaust system is operating normally. Proceed to Test Step 4.
4. Check the Engine Operating Conditions A. 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.	Normal operation	Result: The code was logged during a heavy load. Reduce the load on the engine. Return the unit to service. Result: The code was not logged during a heavy load. Proceed to Test Step 5.
5. Check the Engine Operating Altitude A. Check the engine operating altitude. High altitudes can cause high exhaust temperatures. Consider the operational altitude when troubleshooting a high exhaust temperature. When operating below 5500ft and the ambient temperature is below 30° C (85° F), altitude will not cause a high exhaust temperature derate.	High operational altitudes	Result: The engine was operating at high altitudes. The high exhaust temperature was due to high altitudes. Return the unit to service. Result: The engine was not operating at high altitudes. Contact the Technical Communicator at a Cat® dealer.