A/T - Sluggish Upshifts Or No 4TH Gear When Cold

NO.: 94-I-05

DATE: May, 1994

CORP.NO.: 487102

SERVICE INFORMATION BULLETIN

SUBJECT:
Sluggish Upshifts and/or Upshifts from 1st to 3rd Gear and/or Fails to Shift into 4th Gear Under Cold Operating Conditions - Automatic Transaxles (MP6/MP7) (Information)

MODELS AFFECTED:
1991-1994 Saturns equipped with MP6 or MP7 automatic transaxles.

PURPOSE:
Under very cold operating conditions of -13~C (9~F) or colder, customers may comment that the automatic transaxle has a sluggish upshift or shifts from 1st to 3rd gear without engaging 2nd gear. (This shift from 1st to 3rd gear may feel like a sluggish shift to the customer.) Customers may also notice that the automatic transaxle does not shift into 4th gear. These conditions are normal when the automatic transaxle oil temperature is -13~C (9~F) or colder, and exists until the automatic transaxle warms-up to -12~C (10~F).

Due to a cold weather shift schedule, the powertrain control module (PCM) will shift the automatic transaxle from 1st gear to 3rd gear and not allow a 4th clutch upshift until the automatic transaxle oil temperature sensor senses that oil temperature is -12~C (10~F) or warmer.

IMPORTANT:
This cold weather shift schedule is completely normal and is used to warm-up the automatic transaxle faster, in order to provide smoother shifts.

Also, this cold weather shift schedule will be more noticeable to the customer when outside air temperatures are well below -13~C (9~F). This is due to the extended time required to warm-up the automatic transaxle oil temperature to -12~C (10~F) or warmer.