NUT 4F5677 - Caterpillar

Note: This procedure only applies to engines equipped with Power Take-Off (PTO) switches.Use this procedure under the following circumstances:
The correct supply voltage to the PTO switches is suspect.
Operation of the PTO switches is suspect.Note: Some applications may only have one PTO switch.The PTO switches provide the operator with the ability to select the desired engine speed. Engine speed will decrease with increasing load. The PTO switches can be used to control the engine speed.The engine has the following options of set speed control:
Single speed
No speed (no PTO control)
Illustration 1 g06103129
Schematic for the PTO switches
Not all connectors are shown. Refer to the appropriate Electrical Schematic.
Table 1
Troubleshooting Test Steps Values Results
1. Inspect Electrical Connectors and Wiring
A. Turn the keyswitch to the OFF position.
B. Thoroughly inspect the J1/P1 connectors on the Electronic Control Module (ECM), the switch connections and battery connections. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
C. Perform a 45 N (10 lb) pull test on each of the wires in the switch and ECM connectors that are associated with the diagnostic code. Refer to Illustration 1.
D. Check the screw for the ECM connector for the correct torque of 6 N m (53 lb in).
E. Check the harness for corrosion, abrasion, and pinch points from the PTO mode switches to the ECM.
Loose connection or damaged wire
Result: There is a fault in a connector or the wiring.
Repair: Repair any faulty connectors or replace the wiring harness. Ensure that all the seals are properly in place and ensure that the connectors are correctly coupled.
Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.
Result: All connectors, pins, and sockets are correctly coupled and/or inserted. The harness is free of corrosion, abrasion, and pinch points.
Proceed to Test Step 2.
2. Check the "PTO Mode Switches" on the Electronic Service Tool
A. Turn the keyswitch to the OFF position.
B. Connect the electronic service tool to the diagnostic connector.
C. Turn the keyswitch to the ON position.
D. Observe the status of the PTO mode switch on the electronic service tool while cycling the PTO ON/OFF switch.
E. Use the electronic service tool to observe the status of the PTO mode switch while cycling the PTO Set/Lower switch.
F. Use the electronic service tool to observe the status of the PTO mode switch while cycling the PTO Raise/Resume switch.
Switch status changes from "OPEN" to "CLOSED"
Result: The switch status changes on the electronic service tool as the PTO switches are cycled.
Use the electronic service tool to clear all logged diagnostic codes. Return the engine to service.
Result: The switch status does not change as the PTO switches are cycled.
Proceed to Test Step 3.
3. Check the Status of the PTO Mode Disengage Switches
A. Use the electronic service tool to observe the switch status while the PTO mode disengage switches are operated OFF and ON.
Note: The PTO mode - Disengage switches usually function by the operation of the brake, clutch, or the operator switch. These switches should be operated separately for this test.
Switch status changes from