Spicer TPCS Troubleshooting Guide - Manual (Page 46)

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Service Codes
Group: 9P! (Codes 36, 37, 38)
Type: Inflate Trend
Code Description
Group 9P! displays when system pressure is dropping while
in inflate mode. This can occur when air is leaking from the
tire(s) or the system more quickly than the compressor can
replace it. The air leak that is causing a code 9P! is often audi-
ble. Codes 36, 37 and 38 designate the condition on the front,
rear or trailer channel respectively.
The air leak can be located either before or after the wheel
valve location. The components located before the wheel
valve that may cause a group 9P! include:
• Leaking control lines between the PCU and the wheel
ends.
• Leaking axle air seals.
• Leaking wheel valve inlet lines or exhaust port.
Components located after the wheel valve that may cause a
code 9P! include:
• Tire damage.
• Rim leaks.
• Valve stem leaks.
• Leaking air lines from the wheel valve.
• Faulty wheel valve.
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 9P!
Troubleshooting Tree.
See "Troubleshooting Tips" for general guidelines on system
diagnostics.
System Mode Condition Possible Causes
(Listed in Likely Order of Occurrence)
Channel inoperative Loss of channel pressure in
inflate mode - Damaged or leaking tire.
- Leaking lines.
- Leaking seals.
- Leaking wheel valve.
- Faulty Pneumatic Control Unit.
- Faulty Electronic Control Unit.