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Electronic Control System Gas Plus Engines – FAULT CODE 254 – B LPG

Fuel Shutoff Valve Command Circuit – Shorted Low

Overview

CODE REASON EFFECT
Fault Code: 254
PID: S17
SPN: 632
FMI: 4
LAMP: Red
SRT: 

Fuel Shutoff Valve Command Circuit – Shorted Low. Low voltage (short to ground) detected at the ECM

Fuel shutoff valve closes. Engine will die or will not start.

Fuel Shutoff Valve Command Circuit
SMALL | MEDIUM | LARGE

Circuit Description

The fuel shutoff valve is a solenoid that is used to shut off the flow of gas to the engine. The electronic control module (ECM) controls the fuel shutoff valve.

Component Location

The fuel shutoff valve is located in the fuel housing at the fuel entry point for natural gas engines.

Shop Talk

The ECM will only open the fuel shutoff valve when it detects engine speed. The valve is normally closed when no power is supplied.

Troubleshooting Steps

STEPS SPECIFICATIONS
STEP 1. Check the fault codes.  
  STEP 1A. Check for an inactive fault code. Fault Code 254 inactive?
STEP 2. Check the fuel shutoff valve and circuit.  
  STEP 2A. Inspect the fuel shutoff valve and connector pins. Dirty or damaged pins?
  STEP 2B. Check for an open circuit in the fuel shutoff valve. 12 to 20 ohms?
  STEP 2B-1. Check for a short to ground in the fuel shutoff valve.
  STEP 2C. Check the fuel shutoff valve supply voltage, supply line and return circuit. Greater than 5 VDC?
STEP 3. Check the ECM and engine harness.  
  STEP 3A. Inspect the ECM and engine harness connector pins. Dirty or damaged pins?
  STEP 3B. Check for a pin short circuit to ground. Greater than 100k ohms?
  STEP 3C. Check for a pin to pin short circuit in the engine harness. Greater than 100k ohms?
  STEP 3D. Check for an inactive fault code. Fault Code 254 inactive?
STEP 4. Clear the fault code.  
  STEP 4A. Disable the fault code. Fault Code 254 inactive?
  STEP 4B. Clear the fault codes. All fault codes cleared?

Guided Step 1 – Check the fault codes.

Guided Step 1A – Check for an inactive fault code.

Conditions

  • Turn keyswitch ON
  • Connect INSITE™ electronic service tool.

Action

  • Use INSITE™ electronic service tool to read the fault codes.

Fault Code 254 inactive?
YES NO
No Repair No Repair

Guided Step 2 – Check the fuel shutoff valve and circuit.

Guided Step 2A – Inspect the fuel shutoff valve and connector pins.

Conditions

  • Turn keyswitch OFF
  • Disconnect the fuel shutoff valve from the engine harness.

Action

  • Corroded pins
  • Bent or broken pins
  • Pushed back or expanded pins
  • Wire insulation damaged
  • Moisture in or on the connector
  • Missing or damaged connector seals
  • Connector shell broken
  • Dirt or debris in or on the connector pins.

Refer to the circuit diagram or wiring diagram for component pin identification.

For general inspection techniques, refer to Component Connector and Pin Inspection, Procedure 019-361.

Dirty or damaged pins?
YES NO

A defective connection has been detected in the sensor or harness connector.

Repair the damaged pins. Repair or replace the engine harness, or replace the fuel shutoff valve solenoid, whichever has the damaged pins.

  • Flush the dirt, debris, or moisture from the connector pins using electronic contact cleaner, Part Number 3824510.
  • Install the appropriate connector seal if it is damaged or missing.
  • Repair the engine harness. Refer to Procedure 019-204.
  • Replace the engine harness. Refer to Procedure 019-043.
  • Replace the fuel shutoff valve. Refer to Procedure 019-050.
 No Repair

Guided Step 2B – Check for an open circuit in the fuel shutoff valve.

Conditions

  • Turn keyswitch OFF
  • Disconnect the fuel shutoff valve from the engine harness.

Action

  • Measure the resistance between the fuel shutoff valve OUTPUT pin and the fuel shutoff valve RETURN pin at the fuel shutoff valve connector.

Refer to the circuit diagram or wiring diagram for component pin identification.

For general resistance measurement techniques, refer to the Resistance Measurements Using a Multimeter and Wiring Diagram, Procedure 019-360.

12 to 20 ohms?
YES NO
No Repair

Replace the fuel shutoff valve. Refer to Procedure 019-050.

Guided Step 2B-1 – Check for a short to ground in the fuel shutoff valve.

Conditions

  • Turn keyswitch OFF
  • Disconnect the fuel shutoff valve from the engine harness.

Action

  • Measure the resistance between the fuel shutoff valve SUPPLY pin and ground at the fuel shutoff valve connector.

Refer to the circuit diagram or wiring diagram for component pin identification.

For general resistance measurement techniques, refer to the Resistance Measurements Using a Multimeter and Wiring Diagram, Procedure 019-360.

Greater than 100k ohms?
YES NO
No Repair

Replace the fuel shutoff valve. Refer to Procedure 019-050.

Guided Step 2C – Check the fuel shutoff valve supply voltage, supply line and return circuit.

Conditions

  • Turn keyswitch OFF
  • Disconnect the fuel shutoff valve from the engine harness
  • Turn keyswitch ON.

Action

  • Measure the voltage between the fuel shutoff valve OUTPUT pin and the fuel shutoff valve RETURN pin at the fuel shutoff valve connector of the engine harness.

Greater than 5 VDC?
YES NO
No Repair No Repair

Guided Step 3 – Check the ECM and engine harness.

Guided Step 3A – Inspect the ECM and the engine harness connector pins.

Conditions

  • Turn keyswitch OFF
  • Disconnect the engine harness connector 1 from the ECM

Action

  • Corroded pins
  • Bent or broken pins
  • Pushed back or expanded pins
  • Wire insulation damaged
  • Moisture in or on the connector
  • Missing or damaged connector seals
  • Connector shell broken
  • Dirt or debris in or on the connector pins.

Refer to the circuit diagram or wiring diagram for component pin identification.

For general inspection techniques, refer to Component Connector and Pin Inspection, Procedure 019-361.

Dirty or damaged pins?
YES NO

A defective connection has been detected in the ECM connector 1 or the engine harness connector.

Repair the damaged pins. Repair or replace the engine harness, whichever has the damaged pins.

  • Flush the dirt, debris, or moisture from the connector pins using electronic contact cleaner, Part Number 3824510.
  • Install the appropriate connector seal if it is damaged or missing.
  • Repair the engine harness. Refer to Procedure 019-204.
  • Replace the engine harness. Refer to Procedure 019-043.
No Repair

Guided Step 3B – Check for a pin short circuit to ground.

Conditions

  • Turn keyswitch OFF
  • Disconnect the engine harness connector 1 from the ECM
  • Disconnect the fuel shutoff valve from the engine harness.

Action

  • Measure the resistance between the fuel shutoff valve OUTPUT pin in engine harness ECM connector 1 and engine block ground.

Refer to the circuit diagram or wiring diagram for component pin identification.

For general resistance measurement techniques, refer to the Resistance Measurements Using a Multimeter and Wiring Diagram, Procedure 019-360.

More than 100k ohms?
YES NO
No Repair

A pin to ground short circuit on the fuel shutoff valve output line has been detected in the engine harness.

Repair or replace the engine harness.

  • Flush the dirt, debris, or moisture from the connector pins using electronic contact cleaner, Part Number 3824510.
  • Install the appropriate connector seal if it is damaged or missing.
  • Repair the engine harness. Refer to Procedure 019-204.
  • Replace the engine harness. Refer to Procedure 019-043.

Guided Step 3C – Check for a pin to pin short circuit in the engine harness.

Conditions

  • Turn keyswitch OFF
  • Disconnect engine harness connector 1 and connector 2 from the ECM.
  • Disconnect the fuel shutoff valve from engine harness.

Action

  • Measure the resistance between the fuel shutoff valve SUPPLY pin in engine harness ECM connector 1 to all other pins in the engine connector 1.
  • Measure the resistance between the fuel shutoff valve SUPPLY pin in engine harness ECM connector 1 to all other pins in engine connector 2.

Refer to the circuit diagram or wiring diagram for component pin identification.

For general resistance measurement techniques, refer to the Resistance Measurements Using a Multimeter and Wiring Diagram, Procedure 019-360.

Greater than 100k ohms?
YES NO
No Repair

A pin to pin short circuit on the fuel shutoff valve supply line has been detected in the engine harness.

Repair or replace the engine harness.

  • Flush the dirt, debris, or moisture from the connector pins using electronic contact cleaner, Part Number 3824510.
  • Install the appropriate connector seal if it is damaged or missing.
  • Repair the engine harness. Refer to Procedure 019-204.
  • Replace the engine harness. Refer to Procedure 019-043.

Guided Step 3D – Check for an inactive fault code.

Conditions

  • Connect all components
  • Turn keyswitch ON
  • Connect INSITE™ electronic service tool.

Action

  • Use INSITE™ electronic service tool to read the fault codes.

Fault Code 254 inactive?
YES NO
No Repair

Replace the ECM. Call for pre-authorization. Refer to Procedure 019-031.

Guided Step 4 – Clear the fault codes.

Guided Step 4A – Disable the fault code.

Conditions

  • Connect all components
  • Turn keyswitch ON
  • Connect INSITE™ electronic service tool.

Action

  • Use INSITE™ electronic service tool to verify the fault code is inactive.

Fault Code 254 inactive?
YES NO
No Repair No Repair

Guided Step 4B – Clear the inactive fault codes.

Conditions

  • Connect all components
  • Turn keyswitch ON
  • Connect INSITE™ electronic service tool.

Action

  • Use INSITE™ electronic service tool to erase the inactive fault codes.

All fault codes cleared?
YES NO
No Repair No Repair
Repair complete
Appropriate troubleshooting charts
Last Modified:  09-Sep-2004
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