Spicer CTIS (Central Tire Inflation System) Troubleshooting Guide - Manual (Page 37)

34
Service Codes
Pressure Switch (Code 31)
Pressure Switch (Code 31)
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 open
below psi value shown
in table?
Verify correct vehicle configuration.
See Configuration Error flowchart.
Service code is not active. Reverify
flowchart steps and wait for fault to reoccur.
Is there
continuity?
Repair harness and retest.
Replace pressure
switch and retest
system.
No
Yes
No
Yes
Yes
No
Using the diagnostic tool,
verify pressure switch
status is closed.
Switch off ignition.
Disconnect the ECU connector
and the pressure switch connector.
Verify NO continuity between:
ECU Harness Connector Pins
T and F (round connector)
or
G3 and K2 (rectangular connector)
Part Number
673345 (black)
676770 (blue)
Pressure Switch
Open Value
78 psi
87 psi
Identify vehicle pressure switch:
Part #673345 (black)
Part #676770 (blue)
Use diagnostic tool to
read supply pressure.
Is supply pressure
accurate?
Yes
Replace PCU and recheck system.
Note: While replacing the PCU, pay
particular attention to possible air line
contamination (e.g., oil, water,
particles) which may suggest further
air system maintenance needs.
No
Does fault
reoccur?
Complete
Replace ECU and recheck system.
Note: ECUs are not a typical cause
of problems. If an ECU is replaced,
the system should be carefully
rechecked to make sure the problem
has been fixed and does not reoccur.
No
Yes