Several warning signals report operating problems.
The Central Tire Inflation System uses five general
sequences displayed on the Electronic Control Unit
lights and an instrument panel mounted warning lamp to
identify the type and area of fault.
4 "Mode Lights" Flashing (Check Tire
Conditions) - This signal reports that one tire
may be at a significantly lower pressure than
the others and could indicate that a tire is not
holding air. The system has closed the
wheel valves so the non-damaged tires will
not lose pressure. The operator should
immediately stop the vehicle and identify the
extent of possible tire damage. The system
may be used to re-inflate the low tire if
damage is determined to be minimal (e.g., a
minor puncture to slow leak) by selecting "RUN FLAT."
Repeated use of RUN FLAT to override reoccurring "4
mode lights" warnings may result in tires inflating to
higher than preprogrammed set-points.
NOTE: Excessive air seal leakage on cold weather
start up may result in a "4 mode lights" or "5 mode
lights" warning. If, upon inspection, no tire damage
exists, the operator may proceed to operate the
vehicle. This condition should correct itself (without
the driver selecting RUN FLAT) as the seals warmup
WARNING: RUN FLAT should NOT be used to
attempt inflating tires with substantial damage such
as large cuts, chunkouts, or structural defects. Use of
RUN FLAT in these circumstances can result in other
tires on that channel losing pressure.
5 Lights Flashing - This signal reports that
component and shut off the system, closing
the wheel valves. Since the CTI system
cannot properly function until the fault is
corrected, there is no ability to override.
2 "Mode Lights" on Solid - This signal
reports that the CTI system has shut off
(closing the wheel valves) with the tire
pressure between the two indicated modes.
This occurs when the system is taking too
long to either inflate or deflate the tires.
Pressing any mode key will reattempt a
change of pressures.
No Mode Lights This signal reports that
the CTI system has sensed either a low
system voltage or an electrical fault with a
Pneumatic Control Unit solenoid, and has
shut off the system, closing the wheel
valves until the problem is corrected.
Lights Sequentially Flashing (One after another) This
signal reports that there is a configuration error and the
CTI memory has been "re-loaded" from the system
defaults. Pressing the HWY and RUN-FLAT buttons at
the same time will clear this display Note, however, that
any configurable items (new pressure target, etc.) which
in the past were updated in the ECU have now returned
reprogrammed at the next convenient time.
Buzzer (On instrument panel) This
signal reports that the vehicle speed is
too fast for the pressure selected. The
operator must either reduce speed or
select a higher pressure by pressing
the appropriate key. Continued operation in this mode
will result in the system automatically selecting a more
appropriate pressure setting. In addition, the warning
lamp may flash while the system is in EMERGENCY
mode to caution the driver.
Solid Warning Lamp and/or Buzzer
(On instrument panel) This signal
reports that the ECU has seen 25-50
ignition cycles without seeing any
speed signal. If no problem exists with
speed circuit wiring or sensor, the lamp
will go off when the vehicle is moved In addition, on
vehicles equipped with a buzzer, the buzzer may be
turned off by pressing any mode button on the ECU.
Change 3 3-92.13