HEAD 7Y4932 - Caterpillar

System Operation Description:Use this procedure to troubleshoot the system under the following conditions:
There is an active diagnostic code or a recently logged diagnostic code that is related to the following:
0091-02 Throttle Position Sensor erratic, intermittent, or incorrect
0774-02 Secondary Throttle Position Sensor erratic, intermittent, or incorrectCheck that the software configuration in the Electronic Control Module (ECM) is correct for a multi-position throttle .If the engine has an analog throttle with an Idle Validation Switch (IVS), then refer to Troubleshooting, "Idle Validation Switch Circuit - Test".The throttle switch provides the operator with the ability to select the desired engine speed. The throttle switch configuration may be selected between 0 to 4 switches. A multi-position rotary switch may be used.The throttle switch is typically connected to the four throttle inputs of the ECM. Each position generates a specific ON/OFF pattern on the throttle inputs. A diagnostic code is generated if a pattern that does not correspond with any of the switch positions is detected.Once a diagnostic code is generated, the ECM ignores the throttle input signals. The desired engine speed is set to low idle if no alternative throttle is detected.Voltage at the throttle inputs to the ECM should be 13.8 0.5 Volts DC when the throttle inputs are open. The voltage should be less than 0.5 Volts DC when the throttle inputs are closed.
Illustration 1 g01806833
Schematic for the circuit for the throttle switch
Illustration 2 g01806834
Typical view of the pin locations on the P1 connector for the throttle switch (35) Switch return (49) Throttle position switch 4 (50) Throttle position switch 3 (51) Throttle position switch 2 (52) Throttle position switch 1Test Step 1. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF position.
Thoroughly inspect the P1 connector and any other connectors that are included in the application for this throttle switch. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the sensor connector and the ECM connector that are associated with the active diagnostic code. Refer to illustration 2.
Verify that the latch tab of the connector is correctly latched. Also verify that the latch tab of the connector has returned to the fully latching position.
Check the screw for the ECM connector for the correct torque of 5.0 N m (44 lb in).
Check the harness for corrosion, abrasion, and pinch points from the throttle switch to the ECM.Expected Result:All connectors, pins, and sockets should be completely inserted and coupled. The harness should be free of corrosion, abrasion and pinch points.Results:
OK - Proceed to Test Step 2.
Not OK - Repair: Repair the circuit.Use the electronic service tool in order to clear all logged diagnostic codes and then verify that the repair eliminates the problem.STOPTest Step 2. Check "Throttle Cab Switch Position" on the Electronic Service Tool
Connect the electronic service tool to the diagnostic connector.
Turn the keyswitch to the ON position.
Observe the status of the throttle switch and the throttle inputs on the electronic service tool while you operate the