C175 Oil&Gas Offshore Engine Caterpillar

Fuel Control - Test

Usage:

Use this procedure to troubleshoot the electrical system if a problem is suspected with the Fuel Control Valve (FCV). Also, use this procedure if one of the diagnostic codes in Table 1 is active.

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Table 1
J1939 Code and Description	CDL Code and Description	Comment
1076-7 Engine Fuel Injection Pump Fuel Control Valve : Not Responding Properly	18-7 Fuel Control Valve : Not Responding Properly	The commanded FCV position does not match the actual FCV position.
1076-8 Engine Fuel Injection Pump Fuel Control Valve : Abnormal Frequency, Pulse Width, or Period	18-8 Fuel Control Valve : Abnormal Frequency, Pulse Width, or Period	The PWM signal between the FCV and the ECM has been lost.
1076-12 Engine Fuel Injection Pump Fuel Control Valve : Failure	18–12 Fuel Control Valve : Failure	A failed FCV has been detected.
3597-6 ECU Power Output Supply Voltage #1 : Current Above Normal	1028-6 Power Supply Control 1 : Current Above Normal	A failed power supply to the FCV has been detected.

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Illustration 1	g06334895
Schematic of the PWM signal (primary throttle control) for the high-pressure fuel pump

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Illustration 2	g06334898
Schematic of the PWM signal (secondary throttle control) for the high-pressure fuel pump

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Table 2
Troubleshooting Test Steps	Values	Results
1. Check for Codes A. Apply electrical power to the engine. B. Connect Cat^® Electronic Technician (ET) to the service tool connector. C. Determine if a code is active or logged.	Codes	Result: An 18–7, code is present. Repair: An FCV has been detected. Note: If the pressure is not less than 5000 kPa (725 psi) (gauge) after 10 minutes, vent the pressure from the fuel system. Refer to Systems Operation/Testing and Adjusting, Fuel Rail Pressure - Release, for information. Replace the FCV. Proceed to Test Step 9. Result: An 18–8 code is present. Proceed to Test Step 2. Result: A 1028–6 code is active. Proceed to Test Step 5.
2. Check the Wiring Between the ECM and the FCV for an Open Circuit A. Remove electrical power from the engine. B. Disconnect the FCV from the wiring harness. C. Disconnect the J-1 ECM connector from the engine ECM. D. Measure the resistance between pin-38 on the J-1 ECM connector and pin 11 on the FCV connector.	Open Circuit	Results: There were less than 10 ohms of resistance between pin-38 on the J-1 engine ECM connector and pin 11 on the FCV connector. Proceed to Test Step 3. Results: There were more than 10 ohms of resistance between pin-38 on the J-1 engine ECM connector and pin-11 on the FCV connector. An open circuit in the wiring harness has been detected. Repair: Repair or replace the wiring harness as necessary. Proceed to Test Step 9.
3. Check the Wiring Between the ECM and the FCV for a Short Circuit to Ground A. Remove electrical power from the engine. B. Disconnect the FCV from the wiring harness. C. Disconnect the J-1 ECM connector from the engine ECM. D. Measure the resistance between pin-11 on the FCV connector and a known good ground.	Short Circuit	Results: There were more than 100 K ohms of resistance between pin-11 on the FCV connector and a known good ground. Proceed to Test Step 4. Results: There were less than 100 K ohms of resistance between pin-11 on the FCV connector and a known good ground. A short circuit to ground in the wiring harness has been detected. Repair: Repair or replace the wiring harness as necessary. Proceed to Test Step 9.
4. Check the Wiring Between the ECM and the FCV for a Pin to Pin Short Circuit A. Remove electrical power from the engine. B. Disconnect the FCV from the wiring harness. C. Disconnect the J–1 ECM connector from the engine ECM. D. Measure the resistance between pin-38 on the J–1 ECM connector and all other pins in the J–1 ECM connector.	Short Circuit	Results: There were more than 100 K ohms of resistance between pin-38 on the J-1 ECM connector and all other pins in the J-1ECM connector. Proceed to Test Step 5. Results: There were less than 100 K ohms of resistance between pin 38 on the J–1 ECM connector and all other pins in the J–1 ECM connector. A pin to pin short circuit in the wiring harness has been detected. Repair: Repair or replace the wiring harness as necessary. Proceed to Test Step 9.
5. Check for System Voltage at the FCV connector A. Remove electrical power from the engine. B. Disconnect the FCV from the wiring harness. C. Apply electrical power to the engine. D. Measure the voltage between pin-8 on the FCV connector and a known good ground.	System Voltage	Result: System voltage was present at pin 8. The system is working properly. Result: System voltage was NOT present at pin 8. Proceed to test Step 6.
6. Check for an Open Circuit in the FCV Wiring A. Remove electrical power from the engine. B. Disconnect the fuel control valve from the wiring harness. C. Disconnect the J–1 connector from the ECM. D. Measure the resistance between pin-8 on the fuel control valve wiring harness connector and pin-48 on the J-1 connector.	Open Circuit	Result: There were less than 10 ohms of resistance between the pins. Proceed to Test Step 7. Result: There were more than 10 ohms of resistance between the pins. An open circuit has been detected. Repair: Repair or replace the wiring harness as necessary. If the problem is not resolved, proceed to Test Step 7.
7. Check for a Short Circuit in the FCV Wiring A. Remove electrical power from the engine. B. Disconnect the FCV from the wiring harness. C. Disconnect the J-1 connector from the ECM. D. Measure the resistance between pin-8 on the FCV wiring harness connector and a known good ground.	Short Circuit	Result: More than 100 K ohms of resistance between pin-8 and a known good ground. Proceed to Test Step 8. Result: Less than 100 K ohms of resistance between pin-8 and a known good ground. A short circuit has been detected. Repair: Repair or replace the wiring harness as necessary. If the problem is not resolved, proceed to Test Step 8.
8. Check for a Pin to Pin Short Circuit in the FCV Wiring A. Remove electrical power from the engine. B. Disconnect the FCV from the wiring harness. C. Disconnect the J-1 connector from the ECM. D. Measure the resistance between pin-48 on the J-1 ECM connector and all other pins on the connector.	Short Circuit	Result: More than 100 K ohms of resistance between pin-48 on the J-1 connector and all other pins on the J-1 ECM harness connector. Reconnect the FCV wiring harness and the J-1 connector to the engine ECM. Proceed to Test Step 9. Result: Less than 100 K ohms of resistance between pin-48 on the J-1 connector and all other pins on the J-1 ECM harness connector. A pin to pin short circuit has been detected. Repair: Repair or replace the wiring harness as necessary. If the problem is not resolved, proceed to Test Step 9.
9. Check for Codes A. Start the engine. B. Connect Cat ET to the service tool connector. C. Determine if a code is active or logged.	Diagnostic Codes	Results: No codes are present. Return to service.

If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).