Neutral Flare and/or RPM Flare While In Drive, No 1-2 Upshift, Service Engine Soon (SES) Light Illuminated, Diagnostic Trouble Codes (DTCs) P1810, DTC P1815 Set (Reprogram the Powertrain Control Modul

This bulletin is being revised to add reprogramming of the PCM on 2003 V6 models. Please discard Corporate Bulletin Number 03-07-30-021 (Section 07-Transmission/Transaxle)

Some customers may comment on a neutral flare and/or RPM increase while in drive or no 1-2 upshift and/or the Service Engine Soon (SES) telltale may be illuminated. On 1995-2002 model vehicles, the Powertrain Control Module (PCM) may set a DTC P1810 while on 2003 model vehicles, the PCM may set a DTC P1815.

The cause may be the transmission fluid pressure (TFP) switch (also known as the pressure switch manifold (PSM)). It will be referred to as the TFP switch in this bulletin.

Follow the diagnosis and service procedure below to correct this condition.

VIN BREAKPOINTS

1. If servicing a 2003 Alero, Grand Am, or Malibu with a V6 (RPO LG8 or LA1) for a DTC P1815 built prior to the VIN Breakpoints listed in the table above, REPROGRAM the PCM with the calibrations listed, prior to replacing the TFP switch.




Important: Before installing the new TFP switch, inspect the date code stamped in the switch. The date code MUST BE 2308 or higher. Refer to the illustration above.

2. Replace the TFP switch. Refer to Transmission Fluid Pressure (TFP) Manual Valve Position Switch Replacement (SI Document ID #803989).
3. Clear the code and road test the vehicle.
4. If additional diagnosis is required to correct this condition, refer to

•	For diagnosis of DTC P1810, refer to DTC P1810 (SI Document ID #854362).

•	For diagnosis of DTC P1815, refer to DTC P1815 (SI Document ID #854374).

Parts are currently available from GMSPO.

For vehicles repaired under warranty, use: