GM Service Manual Online
For 1990-2009 cars only

Range

Pressure Switch C - N/O

Pressure Switch D - N/O

Pressure Switch E - N/O

Pressure Switch R - N/C

Switch Status

Scan Tool Status

Switch Status

Scan Tool Status

Switch Status

Scan Tool Status

Switch Status

Scan Tool Status

R

Open

OFF*

Closed

ON

Closed

ON

Closed

ON

N

Closed

ON

Closed

ON

Closed

ON

Open

OFF

1

Open

OFF

Closed

ON

Open

OFF

Open

OFF

2

Open

OFF

Open

OFF

Open

OFF

Open

OFF

3

Closed

ON

Open

OFF

Open

OFF

Open

OFF

4

Closed

ON

Open

OFF

Closed

ON

Open

OFF

5

Open

OFF**

Open

OFF

Closed

ON

Open

OFF

N/C = Normally Closed

N/O = Normally Open

* C pressure switch reverts to the Closed/ON state with throttle applied in Reverse.

** MY 2001 only; in 5th range, C pressure switch remains in the Closed/ON state until 3,900 RPM is attained.