WOMS
P code powertrain Medium severity

P1155 Alternative Fuel Controller

The OBD2 code P1155 indicates a problem with the alternative fuel controller, specifically related to the fuel system's ability to switch between gasoline and an alternative fuel, such as compressed natural gas (CNG) or...

Definition

The OBD2 code P1155 indicates a problem with the alternative fuel controller, specifically related to the fuel system's ability to switch between gasoline and an alternative fuel, such as compressed natural gas (CNG) or propane

Common causes

  • Faulty alternative fuel controller
  • Wiring issues or damaged connectors
  • Faulty fuel pressure sensor
  • Incorrect fuel mixture
  • Malfunctioning fuel injectors
  • Vacuum leaks
  • Faulty engine control module (ECM)
  • Issues with the alternative fuel system components

Common misdiagnoses

  • Faulty oxygen sensors
  • Fuel pressure issues
  • Air intake leaks
  • Mass air flow sensor problems
  • Engine control module (ECM) issues
  • Wiring or connector problems
  • Fuel injector malfunctions
  • Vacuum leaks
  • Exhaust leaks
  • Incorrect fuel type usage

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other trouble codes that may be present. Addressing any related codes can help in diagnosing the issue more effectively

  2. 2. Inspect Wiring and Connectors

    Visually inspect the wiring and connectors related to the alternative fuel system. Look for signs of damage, corrosion, or loose connections that could affect the system's performance

  3. 3. Examine the Alternative Fuel Controller

    If the vehicle is equipped with a separate alternative fuel controller, check its condition. Ensure that it is properly connected and functioning. If necessary, consult the vehicle's service manual for specific testing procedures

  4. 4. Check Fuel Quality

    Ensure that the alternative fuel being used is of good quality and meets the manufacturer's specifications. Contaminated or poor-quality fuel can lead to performance issues

  5. 5. Inspect Fuel System Components

    Check components such as fuel injectors, fuel lines, and pressure regulators for leaks or blockages. Ensure that the fuel system is operating correctly

  6. 6. Test Sensors

    Test any sensors related to the alternative fuel system, such as the fuel pressure sensor or temperature sensor. Faulty sensors can lead to incorrect readings and trigger the P1155 code

  7. 7. Review Engine Parameters

    Use a scan tool to monitor engine parameters while the vehicle is running. Look for any abnormal readings that could indicate a problem with the alternative fuel system

  8. 8. Reset the Code

    After performing any repairs or adjustments, clear the trouble code using the OBD-II scanner and take the vehicle for a test drive to see if the code returns

  9. 9. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the P1155 code for your specific vehicle make and model. Manufacturers may have issued guidance on common issues and fixes

  10. 10. Seek Professional Help

    If the issue persists after performing the above steps, it may be necessary to consult a qualified mechanic or technician who has experience with alternative fuel systems. By following these troubleshooting steps, you can identify and potentially resolve the issue associated with the P1155 code