817070 Mercury DRIVESHAFT HOLDING TOOL

Table 1
Diagnostic Codes Table    
Code and Description    Conditions which Generate this Code    System Response    
E255(1) Diagnostic Reset     The engine's Electronic Control Module (ECM) detects ground on the input for the protection override switch.     If an engine derate or an engine shutdown is active, the derate or the shutdown will be overridden.
The code is logged.    
System OperationIf full engine power is needed, the protection override switch allows the user to override an engine derate or an engine shutdown. The wire for the protection override switch is routed from the ECM to the customer connector. The wire is then routed to a customer supplied switch.
Illustration 1 g01355311
Typical schematic
Illustration 2 g01355312
P1 ECM connector (P1-62) Protection override switch
Illustration 3 g01355313
Customer connector C-C18 (Terminal Z) Protection override switchTest Step 1. Check for an "Active" Event Code
Restore electrical power to the ECM.
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Monitor the event codes on Cat ET. Check and record any event codes.Note: Wait at least 30 seconds in order for the event codes to become active.
Determine if a E255 event code is active.
Activate the protection override switch.
Monitor the event codes on Cat ET. Check and record any event codes.Note: Wait at least 30 seconds in order for the event codes to become active.
Determine if a E255 event code is active.Expected Result:A E255 event code is not active if the protection override switch is in the OFF position. A E255 event code is active if the protection override switch is in the ON position.Results:
OK - The circuit is operating correctly.Repair: The problem may be intermittent. If the problem is intermittent, refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - An event code is not active when the protection override switch is in the ON position. An event code is active when the protection override switch is in the OFF position. Proceed to Test Step 2.Test Step 2. Check the Signal Wire between the Protection Override Switch and the ECM
Disconnect the wire N715-BK from the protection override switch.
Monitor the event codes on Cat ET. Check and record any event codes.Note: Wait at least 30 seconds in order for the event codes to become active.
Determine if a E255 event code is active.
Connect the wire N715-BK to engine ground.
Monitor the event codes on Cat ET. Check and record any event codes.Note: Wait at least 30 seconds in order for the event codes to become active.
Determine if a E255 event code is active.Expected Result:A E255 event code is not active if the wire N715-BK is open. A E255 event code is active if the wire N715-BK is grounded.Results:
OK - The wiring between the ECM and the protection override switch is OK.Repair: The problem is most likely in the protection override switch. Replace the switch.STOP
Not OK - An event code is not active when the wire N715-BK is grounded. An event code is active when the wire N715-BK is open. Proceed to Test Step 3.Test Step 3. Check the Signal Wire between the Customer Connector and the ECM
Disconnect the wire N715-BK from terminal Z of the customer connector.
Monitor the event codes on Cat ET. Check and record any event codes.Note: Wait at least 30 seconds in order for the event codes to become active.
Determine if a E255 event code is active.
Connect wire N715-BK to engine ground.
Monitor the event codes on Cat ET. Check and record any event codes.Note: Wait at least 30 seconds in order for the event codes to become active.
Determine if a E255 event code is active.Expected Result:A E255 event code is not active if the wire N715-BK is open. A E255 event code is active if the wire N715-BK is grounded.Results:
OK - The wiring between the ECM and the customer connector is OK.Repair: The problem is in the wiring between the protection override switch and the customer connector. Repair the wire.STOP
Not OK - An event code is not active when the wire N715-BK is grounded. An event code is active when the wire N715-BK is open. Proceed to Test Step 4.Test Step 4. Check the Signal at the ECM
Disconnect the wire N715-BK from the P1-62 ECM connector.
Fabricate a jumper wire that can be used to replace the signal wire in the ECM connector for the protection override switch. Crimp a connector socket to one end of the jumper wire.
Install the jumper wire into the terminal location for the protection override switch. Ensure that the wire is open.
Connect the ECM connector.
Monitor the event codes on Cat ET. Check and record any event codes.Note: Wait at least 30 seconds in order for the event codes to become active.
Determine if a E255 event code is active.
Connect the jumper wire to engine ground.
Monitor the event codes on Cat ET. Check and record any event codes.Note: Wait at least 30 seconds in order for the event codes to become active.
Determine if a E255 event code is active.Expected Result:A E255 event code is not active if the jumper wire is open. A E255 event code is active if the jumper wire is grounded.Results:
OK - The ECM is operating correctly.Repair: The problem is in the wiring between the ECM connector and the customer connector. Repair the wire.STOP
Not OK - An event code is not active when the jumper wire is grounded. An event code is active when the jumper wire is open.Repair: Replace the ECM. Refer to Troubleshooting, "ECM - Replace".STOP