CONDITION: Some owners of 1991 Saturns with the SOHC (LKO) engine may comment that the engine stalls or hesitates during cold temperature warm-up or after about one minute of operation.
CAUSE: Due to the new federal regulations to address spring and summer Reid Vapor Pressure (RVP) of fuel, warm-up driveability has been impacted.
CORRECTIVE ACTION: Verify stall or hesitation condition during engine warm-up, about one minute after start or just after open to closed loop transition. If condition is verified, proceed with the following steps.
1. Use the scan tool to check for PCM EC/TC codes and flags. If codes or flags are present, refer to the appropriate chart in the "Electronic Engine Controls" or "Automatic Transaxle" service manuals and repair the concern.
If no codes or flags are present, monitor scan tool data and verify all parameters are within specification. Refer to the "Scan Tool General Information Table" in the "Electronic Engine Controls Service Manual."
2. If no codes or flags are present and the scan tool data is within specification, install a new camshaft, powertrain control module (PCM) and calibration. For camshaft replacement, refer to "Camshaft Removal - In-Vehicle" in the "SOHC (LKO) Cylinder Head" section of the "Engine-Mechanical Service Manual."
For PCM replacement, refer to "Powertrain Control Module" in the "Electronic Engine Controls Service Manual."
1991 CALIBRATIONS SOHC (LKO) ENGINES
1438 Manual Transaxles 1442 Automatic Transaxle "Trans Idler" calibration 1440 Automatic Transaxle
PARTS REQUIREMENTS: 21022373 Powertrain Control Module-SOHC (LKO) Manual 21022374 Powertrain Control Module-SOHC (LKO) Auto 21006395 Camshaft
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 T9635 0.5 hrs (Includes PDT [Scan Tool] Parameter and Code/Flag Checks) and Install New PCM ADD: A - Remove and Install 4.5 hrs Camshaft B - With Power Steering 0.3 hrs C - Replace Rocker 0.3 hrs Gasket if Necessary
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.