IDLE SPEED FLUCTUATES (MIL works OK, no DTCs set)

Diagnostic procedure

• 1. Do the PCM Idle Learn  procedure.
• 2. Check the Idle Speed .
• 3. Do the Carbon Accumulation Check .
• 4. Troubleshoot the A/C signal circuit - Refer to:

  A/C Signal Circuit Troubleshooting,  or

  A/C Signal Circuit Troubleshooting (9-Speed A/T) (2019 2020 2021) .

• 5. Check the A/C refrigerant amount - Go to: A/C Refrigerant Recovery/Evacuation/Charging (1234yf)

  NOTE:  Turning the A/C to ON under the conditions that the A/C refrigerant amount is out of specification (excessive or too little) may cause the idle speed fluctuation.

Also check for

• Incorrect valve adjustment
• Intake air leaks