EDGE-CUTTING 7T9781 - Caterpillar

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Schematic for throttle position sensor
Test Step 1. Inspect the Electrical Connectors and the Wiring
Turn the keyswitch to the OFF position.
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Location of the J1/P1 ECM connectors (typical engine view)
(1) J1/P1 ECM connectors
Thoroughly inspect ECM connectors (1). Also, thoroughly inspect the connector for the throttle position sensor. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
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Terminal locations at the P1 ECM connector for the throttle position sensor
(P1-4) 8 VDC supply
(P1-5) Digital return
(P1-66) Throttle position
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Terminal locations for the throttle position sensor
(Terminal 1) 8 V supply
(Terminal 2) Digital return
(Terminal 3) Throttle position
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector and the connector for the throttle position sensor.
Check the allen head screw from each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque value.
Check the harness and the wiring for abrasion and for pinch points. Expected Result:All of the connectors, pins, and sockets are coupled and/or inserted. 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 - The connectors and/or wiring are not OK.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 coupled.Verify that the repair eliminates the problem.STOPTest Step 2. Inspect the Throttle Pedal Assembly
Inspect the throttle pedal assembly for components that are loose, bent, missing, or worn.
Slowly depress the pedal and release the pedal. Expected Result:The throttle pedal assembly operates smoothly without excessive drag. The pedal springs back smoothly to the low idle position without assistance.Results:
OK - The throttle pedal assembly functions properly. The throttle pedal assembly is OK. Proceed to Test Step 3.
Not OK - The throttle pedal assembly is in poor repair.Repair: There is excessive drag or improper operation of the throttle pedal assembly. Repair the throttle pedal assembly or replace the throttle pedal assembly, as required.STOPTest Step 3. Check the Status for "Throttle Position" on Cat ET
Connect the Caterpillar Electronic Technician (ET) to the service tool connector.
Turn the keyswitch to the ON position.
Observe the status for "Throttle Position" on Cat ET while you operate the throttle pedal through the entire range of travel. Expected Result:The status is zero percent when the throttle pedal is released. The status progressively increases to 100 percent when the throttle pedal is fully depressed.Results:
OK - The throttle position sensor is working properly.Repair: The original problem seems to be resolved. There may be an intermittent electrical problem with the harness or the connectors. Refer to Troubleshooting, "Electrical Connectors - Inspect" if the problem is intermittent.STOP
Not OK - The throttle position that is displayed on Cat ET is questionable. Proceed to Test Step 4.Test Step 4. Check the Supply Voltage at the Sensor
Turn the keyswitch to the OFF position.
Disconnect the harness connector for the throttle position sensor.
Turn the keyswitch to the ON position.
Measure the voltage