ENGINE HESITATES OR MAY STALL (INSTALL NEW PCM CALIBRATION). Saturn Saturn 1993

For 1990-2009 cars

# ENGINE HESITATES OR MAY STALL (INSTALL NEW PCM CALIBRATION)

#### SUBJECT: Engine Hesitates or May Stall During Initial Launch, DOHC (LLO) Engines (Install New PCM Calibration)

#### MODELS AFFECTED: All 1993 Saturns with DOHC (LLO) Federal and California engines with automatic transaxles built before, and including VIN PZ229154.

CONDITION: Some customers of 1993 Saturns, equipped with DOHC (LLO) engines and automatic transaxles may comment that the engine hesitates or may stall on initial launches during cold temperature warm-up. The customer may also comment that the engine is hard to start after it stalls.

CAUSE: Due to engine sensitivity to cool ambient temperatures below 4 degrees Celsius (39 degrees Fahrenheit), the engine may hesitate or stall during initial launches.

CORRECTION: Verify that the hesitation or stall condition occurs during initial launches at ambient temperatures below 4 degrees Celsius (39 degrees Fahrenheit) during cold start and warm-up.

#### PROCEDURE:

--------- 1. Using the Scan tool, check for PCM EC/TC codes and flags. If codes or flags are present, refer to the applicable diagnostic charts in the "Electronic Engine Controls Service Manual" and repair the condition. After verifying that condition has been repaired, download the new calibration according to Step 3.

2. If no codes or flags are present, monitor Scan tool data and verify all parameters are within specification. Refer to "Electronic Engine Controls Service Manual." If parameters are not within specification, repair the condition. After verifying that condition has been repaired, download the new calibration according to Step 3.

3. If no codes or flags are present and Scan tool data is within specification, download new calibration using the Saturn Service Stall System or refer to the "Electronic Engine Controls Service Manual."

#### IMPORTANT: Before installing a new calibration, make a note of the transaxle calibration installed, and download the same transaxle calibration with the correct engine calibration.

#### 1993 New ECM Calibration - DOHC (LLO) Engines

3534 DOHC (LLO) Federal engines with automatic transaxles built before, and including VIN PZ229154

3536 DOHC (LLO) California engines with automatic transaxles built before, and including VIN PZ229154

#### IMPORTANT: After the new calibration has been installed, vehicle must be driven until operating temperature is reached. This allows the PCM to relearn variations in the fuel system electronic controls that improve driveability and engine idle.

#### IMPORTANT: Verify that customer comment has been repaired. If problem still exists, refer to diagnostic procedures in the "Fuel/Air Intake/Exhaust Service Manual," and "Electronic Engine Controls Service Manual."

CLAIM INFORMATION: To receive credit for this repair, submit a claim through the Saturn Dealer System as follows:

Labor Case Operation Type Description Code Time ---- ----------- --------- ---- VW PCM EC/TC Calibration T9636 0.3 hrs (Includes PDT Parameter and Code/Flag Checks)

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.