4T40E Auto Trans Intermittent Neutral or No Upshift from 1st to 2nd, or DTCs P1810, P1815, P1816

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

4T40E automatic transmission that exhibits one or more of the following conditions.

Intermittent neutral from a stop or steady speed

No upshift from first to second gear

DTCs P1810, P1815 or P1816

Replace the Transmission Fluid Pressure (TFP) switch (13) and the Transaxle Oil Filter Assembly (85).

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.