SCREW 3F4620 - Caterpillar

Illustration 1 g02160270
Schematic for throttle position sensors
Test Step 1. Inspect the Electrical Connectors and the Wiring
Turn the keyswitch to the OFF position.
Illustration 2 g02133295
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.
Illustration 3 g02160290
Terminal locations at the P1 ECM connector for the throttle position sensor
(P1-1) Throttle position
(P1-4) 8 V supply
(P1-5) Digital return
(P1-66) Throttle position
Illustration 4 g02137756
Terminal locations for the throttle position sensor (typical example)
(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 and the wiring is free of corrosion, of abrasion, and 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 Assembly
Inspect the throttle assembly for components that are loose, bent, missing, or worn.
Slowly actuate the throttle and release the throttle. Expected Result:The throttle assembly operates smoothly without excessive drag. The throttle assembly springs back smoothly to the low idle position without assistance.Results:
OK - The throttle assembly functions properly. The throttle assembly is OK. Proceed to Test Step 3.
Not OK - The throttle assembly is in poor repair.Repair: There is excessive drag or improper operation of the throttle assembly. Repair the throttle assembly or replace the throttle assembly, as required.STOPTest Step 3. Check the Status for "Throttle Position" on Caterpillar Electronic Technician (ET)
Connect the Cat ET to the service tool connector.
Turn the keyswitch to the ON position.
Observe the status for either "Throttle Position" or "Throttle #2 Position" on Cat ET. Operate the throttle through the entire range of travel. Expected Result:The status is zero percent when the throttle is released. The status progressively increases to 100 percent when the throttle is fully actuated.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 across terminal 1 (8 V supply)