GM Service Manual Online
For 1990-2009 cars only

TFP Manual Valve Position Switch Logic

Range Signal

A

B

C

Park/Neutral

ON

OFF

OFF

Reverse

ON

OFF

ON

D4

ON

ON

OFF

D3

OFF

ON

OFF

D2

OFF

ON

ON

D1

ON

ON

ON

Illegal

OFF

OFF

OFF

Illegal

OFF

OFF

ON

ON = 0 volts

OFF = B+ volts