Spicer CTIS (Central Tire Inflation System) Troubleshooting Guide - Manual (Page 60)

57
Service Codes
No Code
Type: Miscellaneous Although the Central Tire Inflation System is self-diagnosing,
there are some operating problems that do not trigger a fault
code. The following chart lists these conditions along with
possible causes and solutions.
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 under that
code.
ELECTRONIC CONTROL UNIT (ECU) DISPLAY
Blank ECU display or DDM display • Power fuse blown
• Bad ground to ECU
• Bad power or switched ignition line
to ECU
• Faulty ECU Check Fuses
See “Power” code
System loses programmed tire pres-
sure settings • Improperly followed programming
procedure
• Faulty ECU Reference programming procedure
Replace ECU
TIRE PRESSURE
Diagnostic tool display shows tires at
higher pressure than target, yet system
does not attempt to deflate Tire pressure rises due to temperature,
are not bled off by the Central Tire Infla-
tion System. This is normal operation. System will only initiate a deflate if a
mode with a lower target pressure than
current target is selected
No apparent inflate or deflate
Pressure imbalance (tires on same
channel at different pressures)
Pressure switch not closed See “Low Air Supply” code
Defective hose, clogged filters See “Tire Leak (Imbalance)” code
No inflate or deflate or particular tire • Valve stem core not removed on tire
• Clogged wheel valve filter or valve
stem Remove hose from tire valve stem and
remove core. Replace hose. Change fil-
ter.
Actual tire pressures do not match pro-
grammed targets.** • Leaking control lines
• Faulty PCU sensor See "Atmospheric" and "Tire Leak
(Imbalance)" codes
Incorrect tire pressures • System defaults to original targets
• Replacement ECU not programmed See “Configuration Error” code
* Possible causes are listed in order of likely occurrence.
** The system is designed to allow tire pressure increase due to heat buildup during vehicle use. This system will not
automatically deflate these pressure buildups—a lower pressure mode must be selected to initiate a deflate.