0391264 JOHNSON MOTOR AND CABLE ASSY.

Table 1
Diagnostic Codes Table
Code 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 code is logged.
446-6 Air Shutoff Relay short The ECM detects a short circuit to ground in the solenoid circuit. The ECM has the ability to stop the engine by shutting off the air supply in an emergency situation. The ECM activates the air shutoff solenoid which activates the air inlet shutoff valve.The first condition occurs when the operator initiates an emergency shutdown. When the shutdown is recognized, fuel is shut off and the air shutoff solenoid is activated. The second condition is for an engine overspeed.The customer can activate the air shutoff solenoid by supplying 24 VDC to terminal 54 of the customer connector.Regardless of the reason for activation, the main power to the ECM must be turned OFF for three seconds in order to reset the engine control.Note: The air shutoff is optional. A programmable parameter needs to be set with Caterpillar Electronic Technician (ET) in order to enable the air shutoff.Note: Ensure that the air shutoffs are manually reset after an emergency stop in order to start the engine again.
Illustration 1 g01382553
Typical schematic
Illustration 2 g01381147
P2 ECM connector
(P2-13) Drive for the air shutoff solenoid
(P2-23) Return for the air shutoff solenoid
Illustration 3 g01381149
Customer connector
(Terminal 54) Air shutoff
Illustration 4 g01234146
Location of ECM connectors
Test Step 1. INSPECT ELECTRICAL CONNECTORS AND WIRING
Turn the main disconnect switch to the OFF position.
Thoroughly inspect the J1/P1 ECM connector and the J2/P2 ECM connector. Inspect all of the connectors that are associated with the circuit. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connectors that are associated with the circuit.
Check the ECM connector (allen head screw) for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Check the harness and wiring for abrasion and for pinch points from the sensors back to the ECM. Expected Result:All connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion and of pinch points.Results:
OK - The harness and connectors appear to be OK. Proceed to Test Step 2.
Not OK - There is a problem with the connectors and/or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem.STOPTest Step 2. CHECK FOR ACTIVE DIAGNOSTIC CODES
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Turn the main disconnect switch to the ON position.
Monitor the active diagnostic code screen on Cat ET. Check the air shutoff system for an active diagnostic code. Note: Wait at least 30 seconds in order for any diagnostic codes to become active.
Activate the override for the air shutoff system. Monitor the active diagnostic code screen on Cat ET. Check the air shutoff system for an active diagnostic code. Note: Wait at least 30 seconds in order for the diagnostic code to become active.
Deactivate the override for the air shutoff system. Expected Result:No diagnostic codes are active.Results:
OK - No diagnostic codes are active.Repair: The problem may be intermittent. If the problem is intermittent, refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - A -6 diagnostic code is active at this time. Proceed to Test Step 3.
Not OK - A -5 diagnostic code is active at this time. Proceed to Test Step 4.Test Step 3. CREATE AN OPEN AT THE CONNECTOR FOR THE AIR SHUTOFF SOLENOID
Disconnect the connector for the air shutoff solenoid.
Monitor the active diagnostic code screen on Cat ET. Check for an active diagnostic code for the air shutoff system. Note: Wait at least 30 seconds in order for the diagnostic code to become active.
Activate the override for the air shutoff system. Monitor the active diagnostic code screen on Cat ET. Check the air shutoff system for an active diagnostic code. Note: Wait at least 30 seconds in order for the diagnostic code to become active.Expected Result:A -6 diagnostic code was active when the solenoid was connected to the circuit. A -5 diagnostic code is active when the solenoid is removed from the circuit.Results:
OK - A -6 diagnostic code was active before disconnecting the connector. A -5 diagnostic code became active after disconnecting the connector. The harness and the ECM are