(SES) Service Engine Soon Light On with Diagnostic Trouble Code (DTC) P0731, No Movement in Drive During Cold Ambient Temperatures (Replace Oil Pump or 1st Gear Sprag Clutch Assembly) #03-07-30-008A - (May 12, 2004)

1998-2002 Saturn S-Series Vehicles

with Automatic Transmissions (MP6/MP7)

Fixed Operations Manager, Parts Manager, and Technician

This bulletin is being revised due to part number and labor operation code changes. Please discard Corporate Bulletin Number 03-07-30-008 (Section 07 -- Transmission/Transaxle).

Condition

Some customers may comment that the vehicle will not move temporarily during cold ambient temperatures of 40°F (4.5°C) and lower. The vehicle will set DTC P0731 after an intermittent loss of forward movement. The customer may also comment that the vehicle will move initially when placed in "R" (reverse) only to experience a temporary loss of forward movement after the shifter is placed in "D" (drive). Immediately following the loss of forward movement, normal vehicle operation and function will be fully restored.

Cause

Two possible causes exist for this condition:

• If there is a temporary leak in the Transaxle Oil Pump Apply Circuit experienced during cold ambient conditions, there may not be enough oil pressure generated from the oil pump to apply the 1st clutch. A DTC will set to indicate 1st gear is unavailable.
• If the 1st Gear Sprag Clutch Assembly malfunctions and does not hold during colder ambient temperatures, no 1st gear and a loss of forward movement will occur, which will set a DTC to indicate that the 1st gear is unavailable.

Both potential causes of this condition may be due to dimensional variation to either component during cold ambient temperatures.

Correction

See procedure to diagnose cause and select the appropriate correction. (Replace oil pump or 1st gear sprag assembly.)

Important

In order to properly diagnose this concern, the vehicle will be required to be parked outside overnight with a pressure gauge connected to the transaxle.

Important

For some 2001 vehicles, it may be necessary to refer to Saturn Technical Bulletin 00-T-76 "No Line Pressure Reading from Auto Trans Line Pressure Ports (Modify Auto Trans Pressure Port) 2001 S-Series".

Procedure:

1. Connect pressure gauge to transaxle, then park vehicle outside overnight.
2. Start vehicle the next day.
• During initial start up, watch the pressure gauge to ensure that adequate line pressure is obtained.

• Caution

  Set the parking brake and keep brakes applied at all times in order to prevent unexpected vehicle motion.

  Select "D" and observe pressure reading and transaxle operation.
3. While duplicating the condition, if line pressure is below 400-600 kPA (58-72 psi) perform the following:
• Remove transaxle from vehicle. (Refer to "Transaxle Removal Procedure" in the Out of Vehicle section of the appropriate Saturn S-Series Automatic Transaxle Service Manual.)
• Remove and replace the oil pump, P/N 21003328, from transaxle. (Refer to the "Transaxle Disassembly Procedure" in the appropriate Saturn S-Series Automatic Transaxle Service Manual.)
4. If normal line pressure (400-600 kPA [58-72 psi]) is observed while duplicating the condition, the oil pump is operating and the following must be performed:
• Remove and replace the 1st Gear Sprag Clutch Assembly, P/N 21003314.
• (Refer to the 1st Driven Gear and 1st Gear One-Way Clutch Assembly" procedures in the appropriate Saturn S-Series Automatic Transaxle Service Manual).
5. Install transaxle and validate repair.

Parts Requirements:

Claim Information:

To receive credit for this repair during the warranty coverage period, submit a claim through the Saturn Dealer System for one or more of the following labor operations:

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer".  They are written to inform these 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 your GM dealer for information on whether your vehicle may benefit from the information.

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