42791 Mercruiser HOLDER AND BRUSH ASSEMBLY

Table 1
J1939 Code and Description CDL Code and Description Comments
2434-1
Engine Exhaust Manifold Bank #1 Temperature #1 : Low - most severe (3) E323 (3)
Low Left Exhaust Temperature The ECM has detected that the HC levels in the SCR catalyst are at a high level. The engine will shut down after a predetermined time.
2434-18
Engine Exhaust Manifold Bank #1 Temperature #1 : Low - moderate severity (2) E323 (2)
Low Left Exhaust Temperature The ECM has detected that the HC levels in the SCR catalyst are at a high level. When the engine is idling or exhaust temperatures are low for extended periods of time, the hydrocarbons in the exhaust stream will collect on the Selective Catalyst Reduction (SCR) catalyst. When enough hydrocarbon has collected on the SCR catalyst, and the exhaust temperatures increase too quickly, the SCR catalyst can be damaged.To protect the hardware in the SCR system, the Electronic Control Module (ECM) monitors how much Hydrocarbon (HC) is building up on the SCR catalyst. The ECM will attempt to increase the engine exhaust temperatures to reduce the amount of hydrocarbon during normal engine operation. In order for this strategy to work, the equipment must be stationary with the parking brake engaged (if equipped).If the engine ECM determines that the ECM cannot get the HC levels below an acceptable threshold after a period, there will be an alert given to the operator to take action. If action is taken, the alert will clear.If the operator is not present, or cannot take action, and the exhaust temperatures do not increase after a certain period, the engine will shut down. The engine may be restarted, but if the engine ECM determines that the exhaust temperatures have not risen high enough or the hydrocarbon levels on the SCR catalyst have not started to drop, the engine will be shut down again.To get the hydrocarbon buildup off the SCR catalyst once the alert or the shutdown has occurred, the operator must either put the equipment to work as soon as possible to elevate the exhaust temperatures to continue to reduce the amount of hydrocarbon on the SCR Catalyst, or the "Aftertreatment System Functional Test" must be performed using Cat® Electronic Technician (ET).Depending on ambient conditions, it may take several "Aftertreatment System Functional Tests" run back to back to get the HC levels on the SCR catalyst back down to an acceptable level. When the low exhaust temperature code goes to logged, the operator must put the machine to work to continue to reduce the HC levels on the SCR catalyst. Failure to put the machine to work may result in more shutdowns.Probable Causes
Codes
TestRecommended Actions
Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Look for active codes that are associated with the system for the event code.
Codes
Result: An associated code is active.
Repair: Troubleshoot any associated codes before continuing with this test.
Result: A code is active or logged.
Proceed to Test Step 2.
2. Perform the "Aftertreatment System Functional Test"
A. Start the engine.
B. Run the engine until normal operating temperature is reached.
C. Connect Cat ET.
D. Select the "Selective Catalyst Reduction System".
E. Use Cat ET to perform the following diagnostic test:
- "Aftertreatment System Functional Test"
Aftertreatment System Functional Test
Result: The test was successful and the codes cleared.
Note: The operator must put the equipment to work to reduce the Hydrocarbon (HC) level on the Selective Catalyst Reduction (SCR) catalyst. Failure to do so will require more service.
Return to service.
Result: The test was successful and the low exhaust temperature code is still active.
Repair: Continue to perform the "Aftertreatment System Functional Test" until the low exhaust temperature codes switch to logged.
Note: The operator must put the equipment to work to reduce the hydrocarbon level on the SCR catalyst. Failure to do so will require more service.
Return to service.
Result: The test was failed.
Repair: Troubleshoot the codes that became active during the test. Refer to the appropriate troubleshooting information.
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).