SEAL 4S6752 - Caterpillar

Note: With the release of Tier 4 Interim/Final engines, additional emissions control system components have been added to the engine to reduce the NOx output. The addition of these components requires three Electronic Control Modules (ECMs) for the engine and aftertreatment systems to operate. The most recent version of Cat® Electronic Technician (ET) must be used when connecting to the Electronic Control Modules. Refer to Special Instruction, REHS8170 for instructions on properly setting up the computer and Comm3 adapter for use on Tier IV applications. When viewing the Diagnostic or Event Codes screens, ensure that the "Include All ECM's" box is checked.Override Parameters
The override parameters screen has multiple overrides. The parameters control various functions on the engine and Clean Emissions Module (CEM). These functions and features allow the technician to troubleshoot different engine systems.Cat ET Location
Connect to Cat ET.
Select the appropriate ECM.
Select the "Diagnostics" tab.
Select the "Diagnostic Tests" tab.
Select the "Override Parameter" tab. Override Parameters Listed in the Engine ECM Menu
Injection Disable Override
This override is used to turn off the fuel injector circuits in order to stop the engine from running.Override Parameters Listed in the Selective Catalyst Reduction Menu
Aftertreatment #1 DEF Return Valve Override
This override turns on the DEF Return Valve circuit in order to test the return valve and the circuit for proper operation.Aftertreatment #1 SCR Dosing Air Assist Valve Command Override
This override turns on the DEF Air Assist Valve circuit in order to test the air assist valve and the circuit for proper operation.Engine Exhaust NOx Level Sensor Power Supply Override
This override turns on the NOx sensor power supply to the engine out NOx sensor in order to test the power supply circuit and the NOx sensor.Aftertreatment #1 Outlet #1 NOx Level Sensor Power Supply Override
This override turns on the NOx sensor power supply to the engine out #1 NOx sensor in order to test the power supply circuit and the NOx sensor.Aftertreatment #1 Outlet #2 NOx Level Sensor Power Supply Override
This override turns on the NOx sensor power supply to the engine out #2 NOx sensor in order to test the power supply circuit and the NOx sensor.Aftertreatment #1 DEF Manifold Heater Relay Override
This override turns on the DEF manifold heater relay in order to test the power supply circuit and the DEF manifold heater.Aftertreatment #1 DEF Tank Refill Solenoid Override
This override turns on the DEF tank refill valve circuit in order to test the refill valve and the circuit for proper operation.Aftertreatment #1 DEF Pump Heater Command Percentage Override
This override is used to turn the DEF pump heater ON or OFF. The value can be 0 percent or 100 percent only.Aftertreatment #1 DEF Pump Drive Command
This override is used to turn the DEF pump ON or OFF. The value can be 0 percent or 100 percent only.Aftertreatment SCR Catalyst Reagent Line Heater #1 Relay State
This override turns on the DEF line heater relay #1 in order to test the power supply circuit and the DEF line heater high side circuit.Aftertreatment SCR Catalyst Reagent Line