WOMS
P code powertrain Medium severity

P0955 ASM Mode Circuit [Perf / Winter / Sport / etc]

The OBD2 code P0955 indicates a malfunction in the ASM (Automatic Shift Management) mode circuit, which affects the performance of different driving modes such as Performance, Winter, or Sport

Definition

The OBD2 code P0955 indicates a malfunction in the ASM (Automatic Shift Management) mode circuit, which affects the performance of different driving modes such as Performance, Winter, or Sport

Common causes

  • Faulty transmission control module (TCM)
  • Wiring issues or damaged connectors
  • Faulty ASM mode switch
  • Low transmission fluid level
  • Transmission fluid contamination
  • Malfunctioning transmission solenoids
  • Software issues or programming errors in the TCM
  • Internal transmission problems

Common misdiagnoses

  • Transmission Control Module (TCM) failure
  • Faulty wiring or connectors
  • Transmission fluid issues
  • Shift solenoid problems
  • Incorrectly calibrated transmission
  • Engine control module (ECM) issues
  • Mechanical transmission problems
  • Sensor malfunctions
  • Software glitches or updates needed
  • Battery or electrical system issues

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other related trouble codes. Sometimes, multiple codes can provide more context for the issue

  2. 2. Inspect Wiring and Connectors

    Visually inspect the wiring and connectors associated with the ASM mode circuit. Look for signs of damage, corrosion, or loose connections

  3. 3. Pay special attention to any connectors that may be exposed to heat or moisture

  4. 4. Check the ASM Switch

    Test the ASM switch (if applicable) to ensure it is functioning correctly. Use a multimeter to check for continuity and proper operation

  5. 5. If the switch is faulty, it may need to be replaced

  6. 6. Inspect the Transmission Control Module (TCM)

    Check the TCM for any signs of damage or malfunction. Ensure that it is properly connected and that there are no issues with the software

  7. 7. If necessary, reprogram or update the TCM software

  8. 8. Examine the Transmission Fluid

    Check the transmission fluid level and condition. Low or dirty fluid can cause transmission issues

  9. 9. If the fluid is low, top it off with the manufacturer-recommended fluid. If it is dirty, consider a transmission fluid change

  10. 10. Test the Transmission Sensors

    Inspect and test any relevant sensors, such as the transmission range sensor or speed sensors, to ensure they are functioning correctly

  11. 11. Replace any faulty sensors as needed

  12. 12. Perform a System Reset

    Clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns. Sometimes, a reset can resolve temporary issues

  13. 13. Check for Software Updates

    Consult with the vehicle manufacturer or a qualified technician to see if there are any software updates available for the TCM or other related systems

  14. 14. Consult Technical Service Bulletins (TSBs)

    Look for any TSBs related to the P0955 code for your specific vehicle make and model. Manufacturers may have issued guidance on common issues and fixes

  15. 15. Seek Professional Help

    If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or transmission specialist for further diagnosis and repair.Conclusion Troubleshooting OBD-II code P0955 involves a systematic approach to identify and resolve issues related to the ASM mode circuit. Always refer to the vehicle's service manual for specific procedures and specifications related to your vehicle