Spicer CTIS (Central Tire Inflation System) Troubleshooting Guide - Manual (Page 43)

40
Service Codes
Between Modes (Codes
23, 24)
Between Modes (Codes 23, 24)
Yes
Verify air system capacity by checking
air system pressure buildup time.
Does the air
supply system
build up?
Repair air supply system
and retest system.
On 2-channel systems, use the diagnostic tool
to identify the faulty channel: front or rear.
Using the diagnostic tool, initiate deflate mode.
Is one tire or axle
group deflating less
than the others?
Are all tires
deflating too
slowly?
On the tires or axles that deflate
slowly, check for:
Restricted QRV exhaust
Clogged wheel valve filters
Plugged tire valve stem
Initiate inflate mode and check
for crimped or restricted lines.
Did system
deflate normally?
Rebuild or replace
wheel valve.
Complete
No
No
No
Yes
Yes
Yes
No
* Reference vehicle build
information for nominal
relief valve pressure.
While
deflating, is the
system (relief valve)
pressure within 1 psig
of nominal? *
Repair PCU restriction and
recheck system.
Is the PCU
vent line or relief
valve plugged or
restricted?
Use diagnostic tool to
manually deflate the tires.
Replace PCU relief valve
and recheck system.
Complete
No
While
deflating, is the
system (relief valve) pressure
within 1 psig of
nominal? *
No
No
Yes
Yes
Yes
Use diagnostic tool to place system
into “pressure check and hold”
mode.
Check for upper control line leaks.
Make repairs to faulty components.