GM Service Manual Online
For 1990-2009 cars only

TFP Manual Valve Position Switch Logic

Range Signal

A

B

C

PARK

OFF

ON

OFF

REVERSE

ON

ON

OFF

NEUTRAL

OFF

ON

OFF

D4

OFF

ON

ON

D3

OFF

OFF

ON

D2

OFF

OFF

OFF

D1

ON

OFF

OFF

Illegal

ON

OFF

ON

Illegal

ON

ON

ON

ON = 0 volts

OFF = B+ volts