C175-16 Locomotive Engine Caterpillar

SCR Catalyst Temperature Sensor - Test

Usage:

Use this procedure to troubleshoot a problem with a Selective Catalyst Reduction (SCR) temperature sensor. Also, use this procedure if one of the following diagnostic codes is active or easily repeated.

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Table 1
J1939 Code and Description	CDL Code and Description	Comments
4360-0 Aftertreatment #1 SCR Catalyst Intake Gas Temperature : High - most severe (3)	E946 (3) High Aftertreatment #1 SCR Catalyst Intake Gas Temperature	The aftertreatment SCR catalyst intake gas temperature sensor has detected that the SCR intake temperature is above the normal operating range.
4360-15 Aftertreatment #1 SCR Catalyst Intake Gas Temperature : High - least severe (1)	E946 (1) High Aftertreatment #1 SCR Catalyst Intake Gas Temperature	The aftertreatment SCR catalyst intake gas temperature sensor has detected that the SCR intake temperature is above the normal operating range.
4360-16 Aftertreatment #1 SCR Catalyst Intake Gas Temperature : High - moderate severity (2)	E946 (2) High Aftertreatment #1 SCR Catalyst Intake Gas Temperature	The aftertreatment SCR catalyst intake gas temperature sensor has detected that the SCR intake temperature is above the normal operating range.
4360-17 Aftertreatment #1 SCR Catalyst Intake Gas Temperature : Low - least severe (1)	E947 (1) Low Aftertreatment #1 SCR Catalyst Intake Gas Temperature	The aftertreatment SCR catalyst intake gas temperature sensor has detected that the SCR intake temperature is below the normal operating range.
4363-0 Aftertreatment #1 SCR Catalyst Outlet Gas Temperature : High - most severe (3)	E950 (3) High Aftertreatment #1 SCR Catalyst Outlet Gas Temperature	The aftertreatment SCR catalyst outlet gas temperature sensor has detected that the SCR intake temperature is above the normal operating range.
4363-15 Aftertreatment #1 SCR Catalyst Outlet Gas Temperature : High - least severe (1)	E950 (1) High Aftertreatment #1 SCR Catalyst Outlet Gas Temperature	The aftertreatment SCR catalyst outlet gas temperature sensor has detected that the SCR intake temperature is above the normal operating range.
4363-16 Aftertreatment #1 SCR Catalyst Outlet Gas Temperature : High - moderate severity (2)	E950 (2) High Aftertreatment #1 SCR Catalyst Outlet Gas Temperature	The aftertreatment SCR catalyst outlet gas temperature sensor has detected that the SCR intake temperature is above the normal operating range.
4363-17 Aftertreatment #1 SCR Catalyst Outlet Gas Temperature : Low - least severe (1)	E951 (1) Low Aftertreatment #1 SCR Catalyst Outlet Gas Temperature	The aftertreatment SCR catalyst intake gas temperature sensor has detected that the SCR intake temperature is below the normal operating range.

The temperature of the exhaust gas is checked by the SCR inlet temperature sensor at the inlet of the SCR canister. The temperature of the exhaust gas is also checked at the outlet of the SCR canister by the SCR outlet temperature sensor (if equipped). These inputs are used to ensure a proper reaction with the SCR catalyst and to properly dose DEF into the exhaust stream.

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Table 2
Troubleshooting Test Steps	Values	Results
1. Check for Codes A. Connect Cat^® Electronic Technician (ET) to the service tool connector. B. Determine if a code is active or logged.	Codes	Result: An E947, E951, 4360-17, or 4363-17 is active or logged. Proceed to Test Step 2. Result: An E946, 4360-0, 4360-15, or 4360-16 is active or logged. Proceed to Test Step 3. Result: An E950, 4363-0, 4363-15, or 4363-16 code is active or logged. Proceed to Test Step 3.
2. Check for Exhaust Leaks A. Start the engine. B. Check the exhaust system for proper installation. C. Check for proper installation of the exhaust system insulation. D. Inspect the exhaust system between the exhaust manifold and the Selective Catalyst Reduction (SCR) catalyst for signs of an exhaust leak. E. Inspect the SCR catalyst temperature sensor to ensure proper installation in the sensor port.	Leaks	Result: There were no exhaust leaks found and the exhaust system insulation is in place and in good condition. Repair: Replace the affected SCR catalyst temperature sensor. Proceed to Test Step 3. Result: There were exhaust leaks found or the exhaust insulation is damaged or missing. Repair or replace damaged or missing exhaust components. Proceed to Test Step 3.
3. Operate the Engine A. Apply electrical power to the engine. B. Start the engine. C. Run the engine until normal operating temperature is reached. D. Connect Cat ET. E. Use Cat ET to monitor the following: - Codes	Codes	Result: A code is not active. Return to service. Result: A code becomes active while running the engine. Repair: Replace the failed temperature sensor. 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).