Spicer CTIS (Central Tire Inflation System) Troubleshooting Guide - Manual (Page 17)

14
Diagnostics
Ser
vice Codes Summar
y
Service Codes Summary
The following chart provides a brief overview of the Central
Tire Inflation System (CTIS) service codes and the effect on
the system. Note: Any reference to a “channel” on a single-channel
system refers to all control lines and wheel ends.
5 Flashing LIGHTs or
DDM – Dashes "--" Code No. Causes (numbered in order of likely occurrence)
Low Pressure 26, 27 CHANNEL PRESSURE LOSS (Channel only checks pressures): Pressure check of
given channel returns low reading (< 5 psig) indicating an extreme loss of pressure.
Repair and request pressure check to clear (press any mode button or run flat).
1) Open or broken line between PCU and wheel valve
2) Significant hub air seal leakage
3) Kinked or plugged line between supply tank and PCU
4) Faulty PCU sensor (ex. frozen water contamination)
5) PCU failure (supply off or control off)
6) Pressure switch failure (shorted closed)
Low Air Supply 32 PRESSURE SWITCH REMAINS OPEN (System non-operative until switch closes):
For 4 minutes at vehicle speed > 20 mph pressure switch failed to close.
Repair and allow pressure switch to close to clear.
1) Compressor governor cutout set too low
2) Pressure switch unplugged, or open wire
3) Faulty pressure switch (failed open)
4) Faulty compressor
5) Broken, kinked, or plugged line from compressor to supply tank
Atmospheric 35 OUT OF RANGE ATMOSPHERIC READING (System waits to check pressures):
Atmospheric pressure check indicates vented PCU pressure is outside of valid
atmospheric range (5-20 psia).
Repair and request pressure check to clear (press any mode button or run flat).
1) Poor ground connection to PCU sensor
2) Faulty PCU sensor (ex, frozen water contamination)
3) Faulty PCU or blocked PCU exhaust vent
Inflate Trend 36, 37 INFLATE PRESSURE LOSS (System disables given channel): Given channel loses > 6
psi while inflating.
Repair and cycle ignition to clear.
1) Damaged tire or tire leakage
2) Leaking lines or seals
3) Faulty PCU (control solenoid off or additional channel stuck on)
Deflate Trend 14 FAILURE TO DEFLATE PROPERLY (System disables deflates): System gains >10 psi
pressure while attempting to deflate, or does not lower tires by even a small amount
of the intended change.
Repair and cycle ignition to clear.
1) Plugged or restricted PCU vent line
2) Faulty PCU relief valve
3) Poor ground connection to PCU sensor
4) Contaminated PCU
5) Faulty PCU