Dodge RAM 1500 1998 Owner's Manual page 2212

DR
MODE SENSOR
DESCRIPTION
The transfer case mode sensor (Fig. 83) is an elec-
tronic device whose output can be interpreted to indi-
cate the shift motor shaft's rotary position. The
sensor consists of a magnetic ring and four Hall
Effect Transistors to create a 4 channel digital device
(non-contacting) whose output converts the motor
shaft position into a coded signal. The TCCM must
supply 5VDC (+/- 0.5v) to the sensor and monitor the
shift motor position. The four channels are denoted
A, B, C, and D. The sensor is mechanically linked to
the shaft of the cam which causes the transfer case
shifting. The mode sensor draws less than 53 mA.
OPERATION
During normal vehicle operation, the Transfer Case
Control Module (TCCM) monitors the mode sensor
outputs at least every 250 (+/-50) milliseconds when
the shift motor is stationary and 400 microseconds
when the shift motor is active. A mode sensor signal
between 3.8 Volts and 0.8 Volts is considered to be
undefined.
Refer to SECTOR ANGLES vs. TRANSFER CASE
POSITION for the relative angles of the transfer case
shift sector versus the interpreted transfer case gear
operating mode. Refer to MODE SENSOR CHAN-
NEL STATES for the sensor codes returned to the
TCCM for each transfer case mode sensor position.
The various between gears positions can also be
referred as the transfer case's coarse position. These
coarse positions come into play during shift attempts.
Transfer Case
Angle (degrees)
Between Gears
+40 (4LO)
Between Gears
Between Gears
+20 (NEUTRAL)
Between Gears
Between Gears
0 (2WD/AWD)
Between Gears
Between Gears
-20 (4HI)
Between Gears
Between Gears
MODE SENSOR CHANNEL STATES
Sensor Channel A
H
H
H
H
H
H
H
H
H
L
L
L
L
1 - MODE SENSOR
SECTOR ANGLES VS. TRANSFER CASE POSITION
Shaft Angle (Degrees)
Sensor Channel B Sensor Channel C
H
H
H
L
L
L
L
L
L
L
L
L
H
TRANSFER CASE - NV243
Fig. 83 Mode Sensor
Transfer Case Position
+40
+20
0
-20
Sensor Channel D
L
L
L
L
L
L
H
H
H
H
H
H
H
21 - 509
4LO
N
2WD/AWD
4HI
H
L
H
H
L
H
H
L
H
H
L
H
H