Spicer TPCS Troubleshooting Guide - Manual (Page 50)

47
Service Codes
Group: 11P! (Codes 44, 45, 46)
Type: Tire Leak (Imbalance)
Air Pressure Check
The Tire Pressure Control 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
Group 11P! indicates that pressure imbalance may exist
between the tires on the front (44), rear (45), or trailer (46)
channel after the system has achieved the target pressure.
This code can be caused by:
• Damaged tire(s) - (tires will continue to lose air after
the vehicle is shut off).
• Leaking air lines between the wheel valve and tire -
(tires will continue to lose air after the vehicle is shut
off).
• Plugged or contaminated wheel valve filter(s) - one
tire of an axle group will deflate slower than others
and 11P! will be set after completion of the deflate
sequence due to one tire being higher in pressure.
• Leaking air lines between the PCU and wheel valve -
tires may not exhibit actual imbalance; air line leaks
between PCU and wheel valve resulted in pneumatic
signature which imitated the fault.
Using a tire pressure gauge to manually compare tire pres-
sures on the indicated channel will allow you to identify the
specific tire involved. Very slow leaks may require that you
allow the vehicle sit overnight for sufficient air loss to occur.
To identify the root cause of the problem, connect the
diagnostic tool (see Diagnostics Section for test equipment
and descriptions) and follow the procedure in the 11P!
Troubleshooting Tree.
See "Troubleshooting Tips" for general guidelines on system
diagnostics.
System Mode Condition Possible Causes
(Listed in Likely Order of Occurrence)
Channel only checks
pressure Tire pressure lower on one
tire than others on same
channel - Minor tire leakage at start-up (leaked down overnight).
- Severe tire damage or leaks.
- Leaking lines.
- Contaminated wheel valve filters.
- Restricted tire valve stem.
- Leaking seals.
- Leaking wheel valve.
- Crimped or restricted control lines.