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P079C Transmission Friction Element "C" Slip Detected

The OBD2 code P079C indicates that the transmission control module has detected a slip condition in the friction element "C" of the transmission, which may suggest issues with the clutch or transmission fluid

Definition

The OBD2 code P079C indicates that the transmission control module has detected a slip condition in the friction element "C" of the transmission, which may suggest issues with the clutch or transmission fluid

Common causes

  • Low transmission fluid level
  • Contaminated transmission fluid
  • Faulty transmission solenoid
  • Worn or damaged transmission components
  • Faulty transmission control module (TCM)
  • Electrical issues (wiring or connectors)
  • Incorrect transmission fluid type
  • Mechanical binding in the transmission
  • Faulty torque converter
  • Software issues in the TCM

Common misdiagnoses

  • Faulty transmission control module (TCM)
  • Worn or damaged transmission components
  • Low transmission fluid level or quality
  • Faulty input or output speed sensors
  • Electrical issues or wiring problems
  • Incorrectly calibrated transmission
  • Engine performance issues affecting transmission operation
  • Faulty torque converter
  • Misinterpretation of other transmission codes
  • Software issues or outdated firmware in the TCM

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other related trouble codes. This can provide more context and help identify if there are other issues affecting the transmission

  2. 2. Inspect Transmission Fluid

    Fluid Level: Check the transmission fluid level. Low fluid can cause slipping

  3. 3. Fluid Condition

    Inspect the fluid for contamination, burning smell, or discoloration. If the fluid is dirty or burnt, it may need to be changed

  4. 4. Fluid Type

    Ensure the correct type of transmission fluid is being used

  5. 5. Examine Transmission Components

    Friction Element "C": Inspect the specific friction element (clutch pack) for wear or damage. This may require disassembly of the transmission

  6. 6. Solenoids and Actuators

    Check the operation of the solenoids and actuators responsible for engaging the friction elements. Faulty solenoids can lead to improper engagement and slipping

  7. 7. Check for Leaks

    Inspect the transmission for any signs of fluid leaks, which could lead to low fluid levels and slipping

  8. 8. Inspect Electrical Connections

    Check the wiring and connectors related to the transmission control module and solenoids for any signs of damage, corrosion, or loose connections

  9. 9. Test the TCM

    If all mechanical and hydraulic components appear to be functioning correctly, the issue may lie with the Transmission Control Module itself. Testing or reprogramming the TCM may be necessary

  10. 10. Perform a Transmission Fluid Flush

    If the fluid is contaminated, performing a transmission fluid flush and replacing the filter may help resolve slipping issues

  11. 11. Road Test

    After performing any repairs or maintenance, conduct a road test to see if the issue persists. Pay attention to how the transmission shifts and if any slipping occurs

  12. 12. Consult Technical Service Bulletins (TSBs)

    Check for any manufacturer-specific TSBs related to the P079C code for your vehicle make and model. There may be known issues or recommended fixes

  13. 13. Professional Diagnosis

    If the problem persists after performing the above steps, it may be necessary to consult a professional mechanic or transmission specialist for a more in-depth diagnosis.Conclusion Addressing a P079C code requires a systematic approach to identify the root cause of the slipping condition. Following these troubleshooting steps can help pinpoint the issue and guide you toward an appropriate solution