C7.1 Engines Caterpillar

SCR Catalyst Has Incorrect Inlet Temperature

Usage:

C7.1 6J6

Show/hide table

Table 1
Diagnostic Trouble Code for Selective Catalytic Reduction (SCR) Catalyst Has Incorrect Inlet Temperature
J1939 Codes	CDL Codes	Code Description (code descriptions may vary)	Comments
4360–10	3105–10	Aftertreatment #1 SCR Catalyst Intake Gas Temperature : Abnormal Rate of Change	The aftertreatment SCR catalyst intake gas temperature sensor has detected an implausible change in temperature.
4360-16	E946 (2)	Aftertreatment #1 SCR Catalyst Intake Gas Temperature : High - moderate severity (2)	The aftertreatment SCR catalyst intake gas temperature sensor has detected that the SCR intake temperature is above the normal operating range.
4360-17	E947 (1)	Aftertreatment #1 SCR Catalyst Intake Gas Temperature : Low - least severe (1)	ECM detects that the SCR catalyst intake temperature is below the acceptable range. The code is logged.
4360-18	E947 (2)	Aftertreatment #1 SCR Catalyst Intake Gas Temperature : Low - moderate severity (2)	The aftertreatment SCR catalyst intake gas temperature sensor has detected that the SCR intake temperature is far below the normal operating range.
Follow the troubleshooting procedure to identify the root cause of the fault.

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

Probable causes

Diagnostic codes
High exhaust temperature
Exhaust system

Note: The procedures have been listed in order of probability. Complete the procedure in the order in which the steps are listed.

Show/hide table

Table 2
Troubleshooting Test Steps	Values	Results
1. Check for Diagnostic Trouble Codes A. Turn the keyswitch to the ON position. Do not start the engine. B. Connect to the electronic service tool. C. Check for associated diagnostic trouble codes.	Diagnostic trouble codes	Result: A 4360-X, E946 (2), or E947 code is active or recently logged. Proceed to Test Step 2. Result: An associated code other than 4360-X, E946 (2), or E947 is active or recently logged. Repair: Troubleshoot the logged or active code. Refer to Troubleshooting, "Diagnostic Trouble Codes". Result: No codes are active or recently logged. Proceed to Test Step 5.
2. Check the Operation of the SCR Catalyst Inlet Temperature Sensor Note : Only perform this step on a cold engine. A. Remove the SCR catalyst inlet temperature sensor and allow the sensor to rest in ambient air for 2 minutes. B. Connect the electronic service tool to the diagnostic connector. C. Monitor the value of the SCR catalyst inlet temperature sensor on the electronic service tool.	Sensor	Result : The value of the SCR catalyst inlet temperature sensor is within ± 9° C (15° F) of ambient temperature. Repair : Reinstall the sensor. torque the sensor to the proper specification. For a 4360-16 or E946 (2) code, proceed to Test Step 3. For a 4360-17, E947 (1), 4360-18 or E947 (2) code proceed to Test Step 4. Result : The value of the SCR catalyst inlet temperature sensor is not within ± 9° C (15° F) of ambient temperature. Repair : Replace the SCR catalyst inlet temperature sensor. Refer to the Disassembly and Assembly manual for more information. Proceed to Test Step 5.
3. Check for Cause of High Temperature A. Check for evidence of an exothermic event in the DOC and DPF. B. Check for evidence of excessive fuel reaching the DOC or DPF	High temperature	Result: There has been an exothermic event in the DOC or DPF. Repair: Replace the Clean Emissions Module (CEM). Result: There is evidence of excessive fuel reaching the DOC or DPF. Repair: Investigate the cause of the excess fuel.
4. Check the Exhaust System A. Check the exhaust system for gas leaks between the Exhaust Back Pressure Regulator (EBPR) and the exhaust tail pipe. B. Check for gas leaks around the following items in the Clean Emissions Module (CEM): · Soot antennas · Temperature sensors · SCR intake NOx sensor · DEF injector C. Check for signs of internal exhaust gas leaks on the outer casing of the CEM. D. Check for missing or damaged exhaust system insulation. E. Make sure that the exhaust piping between the EBPR and the CEM is no longer than 1.83 m (6 ft). F. Make sure that the cooling air flow over the CEM is not excessive for the ambient conditions.	Exhaust System	Result: The exhaust system or the CEM has a gas leak. Repair: Make the necessary repairs. Proceed to Test Step 6. Result: The exhaust system insulation is damaged or missing. Repair: Make the necessary repairs. Proceed to Test Step 6. Result: Review and correct the routing of the exhaust system. If necessary, consult the Dealer Solutions Network (DSN) for further advice. Proceed to Test Step 6. Result: There is excessive cooling air flow over the CEM. Repair: Reduce the cooling air flow. If necessary, consult the Dealer Solutions Network (DSN) for further advice. Proceed to Test Step 6. Result: The exhaust system is OK. Proceed to Test Step 5.
5. Inspect the DPF A. Inspect the inlet of the DPF. Inspect the DPF for a damaged or missing DPF core.	Damaged DPF core	Result: The DPF has a damaged or missing DPF core. Repair: Repair the damaged DPF or missing DPF core. Proceed to Test Step 6.
5. Check the SCR Catalyst Temperature A. Connect to the electronic service tool. B. Run the engine. C. Perform the "Manual Hydrocarbon Dosing Capability Test".	Manual hydrocarbon dosing capability test	Result: The "Manual Hydrocarbon Dosing Capability Test" completed successfully. Return the unit to service. Result: The "Manual Hydrocarbon Dosing Capability Test" failed. An error identifier is generated by the electronic service tool. Repair: Troubleshoot the error identifier. Refer to Troubleshooting, "Service tool Error Identifiers". Repeat Test Step 4. Result: The "Manual Hydrocarbon Dosing Capability Test" failed. No error identifiers are generated. Contact the Dealer Solutions Network (DSN).