Spicer CTIS (Central Tire Inflation System) Troubleshooting Guide - Manual (Page 61)

58
Service Codes
No Code
No Code
Type: Miscellaneous
Condition
Operating problems that do not trigger
a fault code.
Possible Causes*
Since a fault code was not set, these
conditions may be universal and not
call for a troubleshooting routine.
Solution
Where fault codes appear, refer to the
troubleshooting procedures listed
under that code.
AIR LEAKS
Air bleeding from rear axle vents • Air seal leaks (Extreme cold tempera-
tures) Drive vehicle to “warm up” seals
Tires fail to deflate when lower pres-
sures are requested • Pneumatic system problem See “Deflate Signal” code
Leaking tires • Damaged tire
• Loose connection between wheel
valve and tire
• Faulty wheel valve Repair as needed
Air bleeding (audible) through QRV
when ignition is turned off Wheel valve is leaking back through
control lines Identify tire with low pressure and
replace faulty wheel valve
QRV vent plugged Unplug or replace QRV
OTHER
Apparent continuous operation, or slow
inflates or deflates • Too long changing pressures
• Loss of pressure during inflate See “Between Modes”, “Tire Leak (Con-
firm)”, "Inflate Trend" codes
System stopped in middle of inflate or
deflate (display shows steady mode
light before reaching targeted pres-
sures) • Intermittent PCU sensor short or open See “PCU Sensor” code
Wheel end oil leak • Faulty air or oil seal Repair as needed
Optional “load” switch seems to have
no effect • Broken, shorted, or open wire to load
switch
• Faulty load switch - Use diagnostic tool in monitor mode
to verify load status changes when
switch position changes
- Use wiring diagram to test harness
for shorts or open
- Replace load switch
* Possible causes are listed in order of likely occurrence.