DRUM 3Y0511 - Caterpillar

System Operation Description:The throttle position sensor eliminates the mechanical throttle and governor linkages. The sensor that is installed depends on the engine's configuration.
Illustration 1 g01123466
Electronic throttle position sensor
Illustration 2 g01122049
Throttle position sensor with a lever
Illustration 3 g01122050
Throttle position sensor with a knob
Refer to Illustration 4. The sensor creates a Pulse Width Modulated (PWM) signal. The duty cycle varies with the throttle position. The signal has a low duty cycle when the throttle is at low idle. The signal has a high duty cycle when the throttle is at high idle. The Electronic Control Module (ECM) processes the signal in order to control the engine speed.
Illustration 4 g01122143
Duty cycle versus throttle position
The signal from the throttle position sensor has a specific frequency. The frequency of the signal must be between 150 Hz and 1050 Hz or the ECM will activate a 091-08 diagnostic code.
Illustration 5 g01122222
Schematic for the throttle position sensor
Illustration 6 g01120532
Left side view
(1) P61 customer connector
(2) J1/P1 connectors
Illustration 7 g01120532
Left side view
(1) P61 customer connector
(2) J1/P1 connectors
Illustration 8 g01122213
P1 terminal that is associated with the throttle position sensor
(P1-66) Throttle position
Illustration 9 g01122217
J61 and P61 terminal that is associated with the throttle position
(10) Throttle position
Table 1
Troubleshooting Test Steps Values Results
1. Inspect the Electrical Connectors and the Wiring
A. Turn the keyswitch to the OFF position.
B. Thoroughly inspect connectors (1) and (2). Inspect the connections on the throttle position sensor. Refer to Troubleshooting, "Electrical Connectors - Inspect".
C. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the throttle position sensor.
D. Check the allen head screw on each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
E. Check the allen head screw on the customer connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque value.
F. Check the harness and wiring for abrasions and for pinch points from the throttle position sensor to the ECM and from the throttle position sensor to the battery.
Electrical Connectors and Wiring
Result: The wiring and the connectors are OK.
Proceed to Test Step 2.
Result: There is a problem with the wiring and/or the connectors.
Repair: Repair the wiring and/or the connectors. Replace parts, if necessary. Ensure that all of the seals are properly connected. Verify that the repair eliminates the problem.
STOP
2. Check for Supply Voltage at the Throttle Position Sensor
A. Disconnect the P403 connector.
B. Turn the keyswitch to the ON position. The engine should be OFF.
C. Measure the voltage between terminals P403-A and P403-B.
Supply Voltage
Result: The supply voltage is at least 11 VDC for a 12 volt system. The supply voltage is at least 22 VDC for a 24 volt system. The supply voltage is reaching the sensor.
Proceed to Test Step 3.
Result: The supply voltage is incorrect.
Repair: The configuration of the wiring between the +Battery and the throttle position sensor depends on the engine's configuration. The problem could be in the wiring or in a connector. There may be a problem with the battery.
Perform the necessary repairs. Verify that the problem is resolved.
STOP
3. Check