WOMS
P code powertrain Medium severity

P0951 ASM Control Circuit Range/Performance

The OBD2 code P0951 indicates a problem with the ASM (Automated Manual Transmission) control circuit, specifically related to its range or performance, suggesting that the system is not operating within the expected...

Definition

The OBD2 code P0951 indicates a problem with the ASM (Automated Manual Transmission) control circuit, specifically related to its range or performance, suggesting that the system is not operating within the expected parameters

Common causes

  • Faulty ASM control module
  • Wiring issues (shorts, opens, or corrosion)
  • Poor connections or damaged connectors
  • Malfunctioning sensors related to ASM
  • Software issues or programming errors
  • Low battery voltage or electrical system problems
  • Mechanical issues in the ASM system

Common misdiagnoses

  • Transmission control module (TCM) failure
  • Faulty wiring or connectors
  • Incorrect transmission fluid level or type
  • Malfunctioning transmission solenoids
  • Defective speed sensors
  • Engine control module (ECM) issues
  • Mechanical transmission problems
  • Faulty throttle position sensor (TPS)

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other trouble codes that may be present. 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 control circuit. Look for signs of damage, corrosion, loose connections, or frayed wires. Repair or replace any damaged components

  3. 3. Check the ASM Control Module

    If applicable, check the ASM control module for proper operation. Ensure that it is securely mounted and that all connections are tight

  4. 4. Test the Circuit

    Use a multimeter to test the voltage and ground at the ASM control circuit. Compare the readings to the specifications in the vehicle's service manual. Look for any open circuits, shorts, or abnormal resistance

  5. 5. Inspect the Transmission Fluid

    Low or contaminated transmission fluid can affect the performance of the ASM system. Check the fluid level and condition, and replace it if necessary

  6. 6. Check for Mechanical Issues

    Inspect the transmission for any mechanical issues that could affect shifting, such as worn components or low fluid pressure

  7. 7. Perform a System Reset

    Sometimes, clearing the code and resetting the system can resolve temporary issues. After clearing the code, take the vehicle for a test drive to see if the code returns

  8. 8. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the P0951 code for your specific vehicle make and model. Manufacturers may have issued updates or fixes for known issues

  9. 9. Professional Diagnosis

    If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or technician who has experience with your vehicle's transmission and control systems

  10. 10. Replace Faulty Components

    If diagnostics point to a specific faulty component (like the ASM control module or a sensor), replace it as needed. Always refer to the vehicle's service manual for specific diagnostic procedures and specifications related to the P0951 code, as they can vary by make and model