EXPERTEC TSB (93-T-05-SATURN)

Publication date: 1993-01-06
Reference number: 93-T-05-SATURN

EXPERTEC TSB

TECHNICAL SERVICE BULLETIN

Reference Number(s): 93-T-05-SATURN, Date of Issue: 01/06/93

ENGINE STALL/HESITATE DURING OPEN TO CLOSE LOOP TRANS AT COLD TEMPERATURES

Model(s): All 1991 Saturns equipped with SOHC (LKO) Engines

Bulletin No.: 93-T-05-SATURN

Date: 01/06/1993

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.

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.
NOTE: 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."
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."

NOTE: Before replacing camshaft, you must verify that it has not already been replaced. To see which camshaft is installed, refer to the "Vehicle History" to see if the camshaft was replaced with P/N 21006395, or inspect the end of the camshaft. If the number stamped on the end of the camshaft is 21000980, the camshaft must be replaced. (This number is on the opposite end of the camshaft gear.)

For PCM replacement, refer to "Powertrain Control Module" in the "Electronic Engine Controls Service Manual."

NOTE: Both the camshaft and PCM must be replaced. Also, before installing the calibration, make a note of the transaxle calibration installed, and download the same transaxle calibration with the correct engine calibration.

1991 CALIBRATIONS SOHC (LKO) ENGINES

1438 Manual Transaxles
1442 Automatic Transaxle "Trans Idler" calibration
1440 Automatic Transaxle

NOTE: After repair, verify vehicle does not stall or hesitate during the warm-up period. If vehicle still stalls or hesitates during warm-up period, refer to the "Electronic Engine Controls Service Manual" for the correct diagnostic procedures.

PARTS REQUIREMENTS

Parts Number	Description
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:

Fig 1: CLAIM INFORMATION TABLE