Transmission Does Not Upshift When Cold (24 04 97)

TRANSMISSION DOES NOT UPSHIFT WHEN COLD

TECHNICAL SERVICE BULLETIN

TRANSMISSION DOES NOT UPSHIFT WHEN COLD

Model(s): 1988-1992 BMW 735i, 735iL

1988-on BMW 750iL

1989-1993 BMW 535i

1989-1995 BMW 525i

1991-1992 BMW 850i

1992-1995 BMW 325i, 325is, 525iT

1992-1997 BMW 318is

1992-on BMW 318i

1993-1995 BMW 740i

1993-1997 BMW 850Ci

1993-on BMW 740iL

1994-1995 BMW 325iC, 530i, 530iT, 540i, 850Csi

1994-1997 BMW 318iC, 840Ci

1995 BMW M3

1995-on BMW 318ti

1996-on BMW 328i, 328is, 328iC, Z3

1997-on BMW M3, 528i, 540i, 740i

1998-on BMW 323is, 323iC

E31, E32, E34, E36, E38, E39

Group: 24 - Automatic Transmission

Bulletin No.: 24 04 97

Date: November, 1997

SITUATION

Customer may complain of the following:

• Transmission does not want to upshift during the first few minutes of driving following a cold engine start.
• Transmission upshifts at a higher road speed or higher RPM for the first few minutes of driving following a cold engine start.
• Transmission hangs in lower gear during the first few minutes of driving following a cold engine start.

EXPLANATION

In order to reduce vehicle emissions immediately following a cold engine start, the engine will operate in a "warm-up" cycle until the engine operating temperature is reached. The purpose of the "warm-up" cycle is to allow the engine and catalytic converter to reach operating temperature more quickly. In order to get the engine to its operating temperature more quickly the transmission will shift at higher engine/road speeds during this time period. During the "warm- up" cycle the transmission shift points are similar to the shift points used in the "Sport" program. As a benefit to our environment, no changes to this feature are available.

WARRANTY INFORMATION

For information only.