Spicer CTIS (Central Tire Inflation System) Troubleshooting Guide - Manual (Page 27)

24
Service Codes
Low Air Supply (Code 32)
Low Air Supply (Code 32)
When the
governor cuts out, is the
supply pressure greater than
value shown in table? (Use
calibrated pressure gauge
in tank.)
Reset governor cutout
pressure and retest system.
Is the pressure
switch plugged in?
Plug in pressure switch and
retest system.
Using the diagnostic tool, verify
pressure switch operation.
Does the
pressure switch
close above setting
shown in table?
Is
continuity
OK?
Repair harness
and retest.
Verify air system capacity by checking
supply tank pressure buildup time.
Does the
supply tank build
up pressure?
Service code is not active. Reverify
flowchart steps and wait for fault to reoccur.
Repair vehicle air supply
system and retest.
Replace pressure switch
and retest system.
No
Yes
Yes
Yes
No
No
Yes
Yes
No
No
Pressure Switch
Part Number
673345 (black)
676770 (blue)
Minimum Supply
Tank Pressure
120 psig
125 psig
Identify vehicle pressure switch:
Part #673345 (black)
Part #676770 (blue)
Switch off ignition.
Disconnect the ECU connector and
the pressure switch connector.
There are two wires used for the pressure switch (PS).
One is the signal wire. The other connects the pressure
switch to GROUND.
Verify continuity between:
PS Harness ECU Harness
Connector Pin Connector Pin
T (Round Connector)
PS signal or
(pin A or B) G3 (Rectangular Connector)
AND
For Non-M939 Style Vehicle
PS GROUND Vehicle GROUND
(other pin A or B)
For M939 Style Vehicle
PS GROUND
L (Round Connector)
(other pin A or B)
Start pressure build
up in supply tank.