TUBE AS 2603531 - Caterpillar

Illustration 13 g01318220
Terminal locations at the connector for the fuel control valve controller (Terminal 1) Supply (Terminal 5) Return (Terminal 8) Keyswitch (Terminal 11) Throttle control (PWM signal)
Table 3
Troubleshooting Test Steps    Values    Results    
5. Check the Integrity of the PWM Signal at the Controller for the Fuel Control Valve
A. Remove the electrical power from the ECM.
B. Disconnect the harness connector at the controller for the fuel control valve.
C. Connect the leads of a multimeter between terminal 11 (throttle control (PWM signal)) and terminal 5 (return) at the connector for the controller
D. Connect Cat ET to the service tool connector.
E. Restore the electrical power to the ECM. Ensure that the keyswitch is in the ON position.
F. Use the multimeter to measure the duty cycle and the frequency of the PWM signal.
The correct value is approximately 10 percent duty cycle while the keyswitch is in the ON position and the engine is not running. The correct frequency of the signal is 500 Hz.
G. Use Cat ET to override the "Fuel Actuator Position Command". Enter a value of 50 percent for the override parameter.
Note: Wait at least 30 seconds in order for the override to become active.
H. Use the multimeter to measure the duty cycle and the frequency of the PWM signal.
The correct value is approximately 50 percent duty cycle with the "Fuel Actuator Position Command" set to a value of 50 percent. The correct frequency of the signal is 500 Hz
I. Use Cat ET to override the "Fuel Actuator Position Command". Enter a value of 100 percent for the override parameter
Note: Wait at least 30 seconds in order for the override to become active.
J. Use the multimeter to measure the duty cycle and the frequency of the PWM signal.
The correct value is approximately 90 percent duty cycle with the "Fuel Actuator Position Command" set to a value of 100 percent. The correct frequency of the signal is 500 Hz.
K. Remove electrical power from the ECM. Restore all of the wiring to the original configuration.
    Correct PWM Signal    
Results: The duty cycle and frequency are correct for all measurements.
Repair: OK - The ECM is generating the correct PWM signal and the wiring is OK. There is a problem with the fuel control valve controller. Replace the fuel control valve. Verify that the repair eliminates the original problem.
Results: Not OK - The duty cycle is not consistent with the values that are given as the test results. There is a problem in the circuit for the PWM signal. There may be a problem with the ECM.
Proceed to Test Step 6.
   
Table 4
Troubleshooting Test Steps     Values     Results    
6. Check the Integrity of the PWM Signal at the ECM
A. Disconnect the J1/P1 ECM connector.
B. Use a wire removal tool to remove the wire from terminal location P1-38 (throttle control (PWM signal)).
C. Fabricate a jumper wire that is long enough to create a test circuit at the ECM connector. Crimp a connector socket to the end of