GM Service Manual Online
For 1990-2009 cars only

Pressure Switch Manifold (PSM) Logic Early Calibrations

Range

Pressure Switch C

(N/O)

Pressure Switch D

(N/O)

Pressure Switch E

(N/O)

Pressure Switch R

(N/C)

Switch Status

Pressure Status

Switch Status

Pressure Status

Switch Status

Pressure Status

Switch Status

Pressure Status

R

Closed

ON

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

Closed*

ON

Open

OFF

Closed

ON

Open

OFF

N/C = Normally Closed

N/O = Normally Open

Pressure switch remains CLOSED until 3900 rpm output speed is reached and switch staus will change to OPEN and remain OPEN until output speed is reduced to 3700 rpm when the switch status will return to CLOSED.

If early units are updated or were produced later in the 2001 MY, consult the similar table in the 2002 MY information.