VALVE GP-CHECK 1G4376 - Caterpillar

Table 1
Diagnostic Trouble Code for SCR Catalyst Has Incorrect Inlet Temperature
J1939 Code CDL Code Code Description
(code descriptions may vary) Comments
4360-16 E946 (2) Aftertreatment #1 SCR Catalyst Intake Gas Temperature : High - moderate severity (2) The aftertreatment Selective Catalytic Reduction (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) This diagnostic code is only applicable to engines that have a Diesel Particulate Filter (DPF).
The Electronic Control Module (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.
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 4360-16 (E946 (2)) code is active or recently logged.
Proceed to Test Step 2.
Result: A 4360-17 (E947 (1)), or 4360-18 (E947 (2)) code is active or recently logged.
Proceed to Test Step 3.
Result: An associated code other than listed in Table 1 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.
For engines that have a DPF, proceed to Test Step 4.
For engines that do not have a DPF, proceed to Test Step 5.
2. Check for Cause of High Temperature
A. Check for evidence of an exothermic event in the DOC and DPF (if applicable).
B. Check for evidence of excessive fuel reaching the DOC or DPF (if applicable)
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.
Result: There is no evidence of an exothermic event or fuel in the aftertreatment module.
Repair:
Perform the "Aftertreatment Recovery Procedure". Monitor the SCR inlet temperature.
If the SCR inlet temperature is abnormal, install a replacement SCR temperature sensor. Refer to Disassembly and Assembly, Temperature Sensor (Exhaust) - Remove and Install (Selective Catalytic Reduction (SCR) Temperature Sensor).
3. 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 (if equipped)
Temperature sensors
SCR inlet 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