4S/3M Configuration with Stability
(Full and Semi-Trailers)
This is a recommended configuration for spread axle applications. For
For 3M valve applications the 23-valve Control Port 4 is plumbed upstream of
the Stability Module Port 4. That is the 23-valve control signal is taken off before
the Stability Module.
2S/1M
23
S1B
S1A
S2B
S2A
21
22
2S/1M
23
S1B
S1A
2S/2M
2S/2M
S2A
S2B
Full Trailer
(Air or Spring Suspension)
Curb
Road
Full Trailer
(Air Suspension)
Curb
Road
21
22
Semi-Trailer Tandem Axle
(Air or Spring Suspension)
Curb
Road
2S/1M
2S/2M
23
S1B
S1A
S2B
S2A
Semi-Trailer Tri-Axle
(Air Suspension)
Curb
Road
23
S1B
S1A
S2B
S2A
21
22
2S/1M
2S/2M
21
22
Recommended speed sensor wheel locations are
shown in the figures below.
Sensor (S1A, S2A) should be installed on Road Side.
Sensor (S1B, S2B) should be installed on Curb Side.
Make sure sensors are pushed firmly against the
exciter ring.
*
Note:
The pneumatic tube between Stability
Module Port 2 and the ABS Control Port 4 for
the 21 and 22 valve channels should be no longer
than 80” (2 m) in total length for a 3/8-inch diameter
tube. Refer to Page 15 for details on the pneumatic
connections of a 3M system configuration.
The 23 valve is not controlled by the Stability Module.
Legend
Air Hose Line:
Modulator Valves: , ,
Stability Module:
Speed Sensors: S1A, S2A,
S1B, S2B
21
22
23
ITCM
S2B
S1A
21
S1B
S2A
22
23
STABILITY MODULE
INSTALLATION/SERVICE
GUIDE (L31288W)
TM
SM
SM
SM
SM
SM
*
*
*
*
Page 22
