ARM ASSEM. 4D4074 - Caterpillar

Note: With the release of Tier 4 Final engines, additional emissions control system components have been added to the engine to reduce the NOx output. 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 CEM. These functions and features allow the technician to troubleshoot different engine systems.Cat ET Location
Connect to Cat ET.
Select the appropriate Electronic Control Module (ECM).
Select the "Diagnostics" tab.
Select the "Diagnostic Tests" tab.
Select the "Override Parameter" tab.Override Parameters Listed in the Engine ECM Menu
Air Shutoff
This override energizes the air shutoff circuit that provides power from the ECM to the air shutoff solenoid to test for proper operation.EGR Valve Control Override
This override allows the user to energize the solenoid that controls the oil flow into the exhaust gas recirculation (EGR) valve to test for proper operation.EGR Valve #2 Control Override
This override allows the user to energize the solenoid that controls the oil flow into the exhaust restriction valve (ERV) to test for proper operation.Electric Fuel Transfer Pump Relay Override
This override energizes the clean fuel module pump circuit that provides power from the ECM to the clean fuel module pump relay to test for proper operation.Engine Crankcase Ventilation Heater Relay Status
This override energizes the crankcase ventilation heater circuit that provides power from the ECM to the crankcase ventilation heater relay to test for proper operation.Engine Fan Bypass
This override allows the operator to activate the engine cooling fan to any duty cycle between 0 percent and 100 percent.Engine Overspeed Test
This test is used to test the engine overspeed shutdown protection system. When this test is activated, the ECM will temporarily lower the engine overspeed shutdown limit to 75 percent of the normal value. The usual method of engine speed control is then used to raise the engine speed above the temporary speed threshold. The ECM will then disable injection and shutdown the engine. Once the test is complete, the ECM must be reset using a keyswitch cycle before the engine can be restarted.
Ether Injection Override
This override energizes the ether injection circuit that provides power from the ECM to the ether injection relay to test for proper operation.Fuel Pump Relay Command Override
This override energizes the fuel priming pump circuit that provides power from the ECM to the fuel priming pump relay to test for proper operation.Starter Override
This override energizes the fuel starter relay circuit that provides power from the ECM to the engine starter relay to test for proper operation.System Troubleshooting Settings
The "System Troubleshooting Settings" screen will allow overrides to be enabled.Cat ET Location
Connect to Cat ET and select the appropriate ECM.
Select the "Diagnostics" tab.
Select the "Diagnostic Tests" tab.
Select "System Troubleshooting Settings".Active Diagnostic Codes
The purpose