Spicer CTIS (Central Tire Inflation System) Troubleshooting Guide - Manual (Page 28)

25
Service Codes
5 Flashing Lights or DDM – Dashes "--" (Code 35)
Type: Atmospheric
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 the tires for approximately two seconds while
monitoring the pressure.
Code Description
An “Atmospheric” code is logged if the atmospheric pressure
reading is out of range. The atmospheric pressure reading can
be out of range as a result of a blocked or restricted Pneu-
matic Control Unit (PCU) or vent line, contaminated PCU sen-
sor (i.e. frozen water), air bleeding back into the PCU or
because of a faulty PCU sensor.
The components that can cause this code to be set include:
• Faulty or contaminated PCU sensor
• Faulty or contaminated PCU
• Faulty Electronic Control Unit (ECU)
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 Atmospheric
troubleshooting tree.
See “Troubleshooting Tips” for general guidelines on system
diagnostics.
System Mode Condition Possible Causes (listed in order of likely occurrence)
System waits to
check pressures PCU pressure out of range
when PCU is “vented” • Frozen water or other contaminant in PCU sensor
• Plugged PCU vent
• Poor ground connection to PCU sensor
• Faulty PCU sensor
• Faulty PCU
PCU Sensor Harness Connector
T S
A B
C
U
R
P
a
b
c
V
D
E
F
G
W
H
X
J
K
Y L
M Z
N
ECU Harness Connector
A B C D E
A B C D E
A B C D E
F G H J K 3
2
1
F G H J K
F G H J K
C A B
A B
C
– or –
– or –