GEAR-RING 7D2626 - Caterpillar

System Operation Description:Use this procedure to determine if the circuit for the PTO engine shutdown switch is operating correctly.Background InformationAn input is available to the Engine Control Module (ECM) for connecting a switch to shut down the engine while the engine is operating in PTO mode. To use this feature, the "PTO Configuration" parameter must be programmed to "Cab Switches", to "Remote Switches", or to "Remote Throttle". The following conditions must also be met in order to use this feature:
"PTO Engine Shutdown Switch" must be programmed to "P1/J1:7" or to "P1/J1J1:23".
The PTO On/Off Switch is in the ON position and the PTO is active.
The PTO Engine Shutdown Switch is in the ON position.
186-04 is not active.
The vehicle speed is equal to zero.
No vehicle speed faults are active.If the vehicle speed is not equal to zero, or if there are active vehicle speed faults, the engine will go to low idle. The engine will not shut down when the vehicle speed falls to zero. When the PTO engine shutdown switch is pressed, a 186-14 will become active. The code will stay active until the engine shuts down. When the engine shuts down, the code will be logged.
Illustration 1 g01152403
Typical circuit schematic for the PTO engine shutdown switch
The return wire may be connected to P1-3, P1-5, or P1-18.
Note: The PTO engine shutdown switch may also be connected to P1/J1-7 Input 4. The parameter "PTO Engine Shutdown Switch" must be programmed to "P1/J1:7".Test Step 1. Inspect Electrical Connectors and Wiring
Illustration 2 g01152420
Pin locations on ECM connector
(P1-3) Sensor common 2
(P1-7) PTO engine shutdown (switch can be connected to pin 7 or to pin 23
(P1-23) PTO engine shutdown (switch can be connected to pin 7 or to pin 23
Thoroughly inspect the ECM vehicle harness connector J1/P1, the connectors, and the firewall bulkhead connectors. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the suspect switch circuit.
Check the ECM connector (allen head screw) for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Check the harness and the wiring for abrasion and for pinch points from the battery to the ECM. Then, check from the ignition key switch to the ECM. Refer to Illustration 2 for terminal locations for 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 - Proceed to Test Step 2.
Not OK - Repair the wiring and connectors or replace the wiring or the connectors. Ensure that all of the seals are properly connected. Verify that the repair eliminates the problem.STOPTest Step 2. Check the Switch Status on Caterpillar Electronic Technician (ET)
Connect Cat ET to the data link connector.
Turn the ignition key switch to the ON position.
Operate the switch in the ON position and the OFF position.
View the switch status on Cat ET.
If the switch status indicates "Not Installed", the parameter "PTO Engine