6.5L L65 Diesel Engine Idle Surge, Rough Idle, or Idle Flare No DTCs

When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

Idle surge, rough idle, or idle flare no DTCs

Observe the fuel rate at idle with the Tech 2. Normal fuel rate at idle for automatic transmissions is 10-13MM3 and for manual transmissions, 8-11MM3. If low fuel rate is found:

1. Check engine oil level.
2. Check crank case for high pressure, reference SI document number 727092.
3. If high crank case pressure is found, verify CDRV valve or hoses not restricted.
4. Check for oil leakage past the turbocharger seals, reference SI document number 203626.
5. If none of the above is found, complete diesel diagnostic worksheet, reference Bulletin 00064B in SI and call GM TAC.

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.