Spicer CTIS (Central Tire Inflation System) Troubleshooting Guide - Manual (Page 40)

37
Service Codes
4 Flashing Lights or CHECK TIRES Flashing (Codes 41, 42)
Type: Tire Leak (Confirm)
Note: RUN FLAT overrides this fault.
Air Pressure Check
Note that the Central Tire Inflation System is not continuously
pressurized; pressure checks occur on a periodic basis.
During tire pressure checks, the system delivers compressed
air to each channel for approximately two seconds while
monitoring the pressure in that channel.
Code Description
A “Tire Leak” occurs if a channel fails to confirm tire pressure.
Following an inflate or deflate sequence, the Central Tire
Inflation System will return to confirm, or “double-check” the
new pressure. If the pressure has dropped, the system will re-
inflate, and then reconfirm the tires. After multiple failed
confirmation attempts, the system will log a Tire Leak
(Confirm) code and the system will become inoperative.
A confirmation failure can be caused by:
• Damaged or leaking tire
• Leaking air line between the wheel valve and tire
• Plugged or restricted Quick Release Valve (QRV)
• Leaking wheel valve
• Plugged or restricted Pneumatic Control Unit (PCU)
vent line
• Restricted air passage between QRV and wheel valve
To correctly diagnose the faulty component, connect the Diag-
nostic Tool (see "Diagnostics" for test equipment and descrip-
tions) and follow the procedure in the Tire Leak
(Confirm) troubleshooting tree.
See “Troubleshooting Tips” for general guidelines on system
diagnostics.
System Mode Condition Possible Causes (listed in order of likely occurrence)
Channel inopera-
tive Channel confirmation failure • Damaged or leaking tire
• Leaking line between wheel valve and tire
• Plugged or restricted QRV
• Leaking wheel valve
• Plugged or restricted PCU vent line
• Restricted air passage between QRV and wheel valve