0395391 JOHNSON RECTIFIER & REGULATOR ASSY.

Table 1
Diagnostic Codes Table    
CDL Code and Description     Conditions which Generate this Code     System Response    
337-2 Remote Emergency Stop Switch : Erratic, Intermittent, or Incorrect     The two inputs from the emergency stop switch are in the opposite state.     The code is logged.    
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 code is logged.    
446-6 Air Shutoff Relay short     The ECM detects a short circuit to ground in the solenoid circuit.    The ECM will stop the engine in an emergency situation by shutting off the air supply to the engine. The ECM energizes the circuit for the air shutoff solenoid. The solenoid supplies air pressure that trips the air shutoff valves for both sides of the engine. The air shutoff solenoid is located on the air shutoff mechanism that is for the right side of the engine.This system also incorporates two switches that monitor the position of the air shutoff mechanisms. If the air shutoff mechanisms are closed, the switches complete a circuit that is wired to a low side ECM driver. The ECM detects this condition and the ECM logs an event code.The air shutoff system is optional for this application. Use Caterpillar Electronic Technician (ET) to program Air Intake Shutoff Detection Installation Status to "Installed" in order to enable the air shutoff system.There are two conditions which can cause the ECM to activate the air shutoff:Engine Overspeed - The first condition occurs when the ECM detects an engine overspeed. During an engine overspeed, the ECM energizes the circuit for the air shutoff solenoid. An event code is generated for this condition. Once an event for the air shutoff system is activated, the event is latched until electrical power to the ECM system is cycled.Emergency Stop Sequence - The second condition occurs when one of the emergency stop switch is activated. When an emergency stop switch is placed in the STOP position, voltage is supplied directly to the air shutoff solenoid. The solenoid energizes and the air shutoff mechanisms are closed.Ensure that both of the air shutoff mechanisms are manually reset after activating the air shutoff system in order to start the engine again. The main power to the ECM must be turned OFF for 30 seconds to reset the engine control.Use Cat ET to view the "Air Intake Shutoff Position" parameter in order to confirm the status of the air shutoff system.
Illustration 1 g01827000
Schematic for the air shutoff system
Illustration 2 g02616804
Location of the connectors at the control box that are for the fuel control (typical top front engine view) (1) Right rail connector (2) J2/P2 ECM connector (3) J1/P1 ECM connector (4) Left rail connector (5) Connector for the primary power harness (6) Engine interface connector
Illustration 3 g02784334
Location of the components at the air shutoff mechanism (right side engine view) (7) Air shutoff solenoid (8) Air shutoff switch
Illustration 4 g01560819
Terminal locations at the P1 ECM connector for the air shutoff system (P1-19) Shutdown output (P1-41) Position of the air shutoff
Illustration 5 g01560820
Terminal locations at the P2 ECM connector for the air shutoff system (P2-14) Digital return
Table 2
Troubleshooting Test Step    Values    Results    
1. Inspect the Electrical Connectors and the Wiring
A. Turn the battery disconnect switch to the OFF position.
B. Verify that the air shutoff mechanisms are set to the OPEN position.
C. Thoroughly inspect connectors (1) and (6). Also, inspect the connectors at the air shutoff mechanism that are for solenoid (7). Also, inspect switches (8) for the air shutoff that are on both sides of the engine. Refer to Troubleshooting, "Electrical Connectors - Inspect"
D. Perform a
45 N (10 lb) pull test on each of the wires that are associated with the circuit for the air shutoff system.
E. Check the allen head screw on each ECM connector for the proper torque. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
F. Check the harness and the wiring for abrasion and for pinch points from the air shutoff solenoid to the ECM.
   
Connectors    
Results: The connectors and wiring appear to be OK.
Proceed to Test Step 2
Results: The connectors and/or wiring are not OK.
Repair: Repair the wiring and/or the connectors. Replace parts, if necessary. Ensure that all of the seals are properly in place and ensure that the connectors are coupled. Verify that the problem is resolved.
   
Table 3
Troubleshooting Test Step    Values    Results    
2. Test the Operation of the Control Solenoid for the Air Shutoff Relay and Check for Logged Codes
A. Connect Cat ET to the service tool connector.
B. Turn the battery disconnect switch to the ON position.
C. Test the air shutoff system with the emergency stop switch:
a. Start the engine.
b. Place the emergency stop switch in the STOP position.
c. Check the position of the air shutoff mechanisms. Activation of the emergency stop will activate the air shutoff system and the air shutoff mechanisms will close.
Check that the solenoid has de-energized after the air shutoff mechanisms are closed.
d. Turn the battery disconnect switch to the OFF position.
D. Check the status of the "Air Intake Shutoff Position" parameter in Cat ET.
a. While both of the air shutoff mechanisms are shut, check the status of "Air Intake Shutoff Position" by usin