KNOB-ENGINE START 2W0629 - Caterpillar

System Operation Description:Use this procedure to troubleshoot the electrical system if a problem is suspected with the circuit for the fuel control solenoid or if one of the diagnostic codes in Table 1 is active or easily repeated.
Table 1
Diagnostic Codes Table    
Code and Description    Flash Code    Conditions which Generate this Code    System Response    
17-5 Fuel Shutoff Valve : Current Below Normal     45     The solenoid voltage is less than 0.75 VDC. Also, the engine speed is greater than 500 rpm for ten seconds. No faults are present.     The code is logged.
The shutoff solenoid is de-energized. The shutoff solenoid is energized after the fault is cleared.    
17-6 Fuel Shutoff Valve : Current Above Normal     45     The solenoid voltage is above 2.5 VDC. Also, the engine speed is greater than 500 rpm for ten seconds. Also, there are no faults for the supply voltage. Also, the supply voltage does not have a fault.     The code is logged.
The shutoff solenoid is de-energized. The shutoff solenoid is energized after the fault is cleared.    The Electronic Control Module (ECM) contains the logic and the outputs for control of starting the engine and stopping the engine. Some of the logic for starting the engine and for stopping the engine is customer programmable. The logic responds to inputs from the following components: engine control switch, emergency stop switch and other inputs.The ECM outputs a signal to the fuel control solenoid in order to control the fuel shutoff valve. To enable fuel flow to the engine, the fuel control solenoid must be energized. The fuel control solenoid may be controlled by the ECM or by the customer's equipment. Use this procedure to troubleshoot either configuration.The most likely cause of a diagnostic code is a poor electrical connection or a problem in a wiring harness. The next likely cause may be a problem with the fuel control solenoid. The least likely cause is a problem with the ECM.The following information describes the system's operation when the fuel shutoff valve is controlled by the ECM:The ECM sends an output signal to the fuel control solenoid that controls the operation of the fuel shutoff valve. This output is energize-to-run. During the crank cycle, when the engine speed exceeds 50 rpm, the ECM provides a voltage of +Battery to the output for the fuel control solenoid. The solenoid becomes energized. This initiates fuel flow to the engine. The ECM removes the voltage from this output in order to stop the engine. The fuel control solenoid becomes de-energized. This stops the fuel flow.
Illustration 1 g01627351
Illustration 2 g01635794
(22) Fuel shutoff solenoid (33) Solenoid groundTest Step 1. Inspect the Electrical Connectors and the Wiring Harness
Remove electrical power from the ECM.
Thoroughly inspect the P5/J5 connector for the fuel shutoff solenoid. Inspect the ECM J14/P14 connector. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit for the