ROD 2394340 - Caterpillar

System Operation Description:Use this procedure to troubleshoot the electrical system if a problem is suspected with the air shutoff system or if any one of the event codes or diagnostic codes in Table 1 is active or easily repeated.
Table 1
Diagnostic Codes Table    
Description     Conditions which Generate this Code     System Response    
446-5 Air Shutdown Relay current below normal     The Electronic Control Module (ECM) detects an open circuit and/or a short to the +Battery in the solenoid circuit. The configurable parameter for the air shutoff is set to "Enabled".     The code is logged.    
446-6 Air Shutoff Relay short     The ECM detects a short circuit to ground in the solenoid circuit. The configurable parameter for the air shutoff is set to "Enabled".    
E2087(3) Air Intake Shutoff Closed     The ECM detects an "Active" condition in the detection circuit that monitors the state of the air shutoff valves. The configurable parameter for the detection circuit is set to "Installed".     The code is latched until power is cycled to the ECM. The process for starting the engine will be stopped and the process for starting the engine will be disabled. If engine rpm is present, the air shutoff relay will be activated.
The code is logged.    
E2088(1) Air Intake Shutoff Detection Circuit Detected but Not Installed     The ECM detects an "Active" condition in the detection circuit that monitors the state of the air shutoff valves. The configurable parameter for the detection circuit is set to "Not Installed".     The code is logged.    The engine's ECM has the ability to stop the engine by cutting off the inlet air supply in an emergency situation. The ECM activates the air shutoff solenoid in order to close the air shutoff valve. The air shutoff is optional. A programmable parameter needs to be set to "Installed" with Caterpillar Electronic Technician (ET) in order to enable the air shutoff system.There is a switch at each of the air shutoff valves that is included in a detection circuit that inputs a signal to the engine ECM. The ECM monitors the input from the detection circuit in order to determine if the air shutoff valves are in the closed position. If the circuit indicates that the air shutoff valves are closed, the ECM will generate the E2087 event code.There are three conditions which cause the engine control to activate the air shutoff solenoid. The first condition occurs when the operator initiates an emergency shutdown. When the emergency shutdown is recognized, fuel is shut off and the air shutoff solenoid is activated. The second condition is for an engine overspeed. The third condition occurs when engine rpm is present and the detection circuit indicates an "ACTIVE" input to the ECM.The input for the air shutoff switch is "NOT ACTIVE" when the switch circuit indicates an open circuit between terminal P1-55 and terminal P1-56. The input for the air shutoff switch is "ACTIVE" when the switch circuit indicates