Page 49 - Hydra-matic 6 Speed RWD Technician's Guide (October 2005)

ELECTRICAL COMPONENTS

SLIDING
ACTUATOR

TRANSMISSION MANUAL SHIFT
SHAFT POSITION SWITCH ASSEMBLY
(308)

TRANSMISSION MANUAL SHIFT SHAFT POSITION Manual Shift Shaft Position Switch Logic
SWITCH ASSEMBLY (308):
The transmission manual shift shaft position switch assembly Gear Selector Position Signal A Signal B Signal C Signal P
(308), sometimes referred to as an Internal Mode Switch (IMS),
is a sliding contact switch that connects to the manual valve Park LOW HI HI LOW
located inside the control valve lower body assembly. The four Park/Reverse LOW LOW HI LOW
inputs to the TCM from the position switch assembly indicate Reverse LOW LOW HI HI
which transmission gear range is selected. The state of each
input is available for display on the scan tool. The four input Reverse/Neutral HI LOW HI HI
parameters represented are Signal A, Signal B, Signal C, and Neutral HI LOW HI LOW
Signal P (Parity).
Neutral/Drive 6 HI LOW LOW LOW
A fifth input, signal N (P/N Start), does not input the TCM but Drive 6 HI LOW LOW HI
rather goes directly to the ECM to determine a Park/Neutral Drive 6/Drive 4 LOW LOW LOW HI
state and allow engine start. Routing Signal N to the ECM will
allow the engine to be started with a dead TCM. Signal N is not Drive 4 LOW LOW LOW LOW
a signal used by the TCM for manual shift shaft position switch Drive 4/Drive 3 LOW HI LOW LOW
logic.
Drive 3 LOW HI LOW HI
Drive 3/Drive 2 HI HI LOW HI
Drive 2 HI HI LOW LOW
Open HI HI HI HI
If the TCM detects an improper signal from the transmission Invalid HI HI HI LOW
manual shift position shaft switch assembly, a DTC will be Invalid LOW HI HI HI
activated.

HI = Ignition Voltage
LOW = 0 Volts

40 Figure 36