87734 Mercruiser SPRING, IDLE NEEDLE

Complete the procedure in the order in which the steps are listed.Probable causes
Diagnostic codes
High exhaust temperature
Exhaust systemNote: The procedures have been listed in order of probability. 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-X, E946-2, or E947-X code is active or recently logged.
Proceed to Test Step 2.
Result: An associated code other than 4360-X, E946-X, or E947-X 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 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 5.
Result: The exhaust system insulation is damaged or missing.
Repair: Make the necessary repairs.
Proceed to Test Step 5.
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 5.
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 5.
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).