Spicer TPCS Troubleshooting Guide: Older Systems (ECU's w_Dual Connectors) - Manual (Page 38)

38
Troubleshooting
Code Description
Code 4P! displays if a channel inflates or deflates too slowly. The
maximum allotted time for each channel is 40 minutes for an inflate, or
20 minutes for a deflate. The most likely cause is a faulty compressor
or similar problem resulting in inadequate air supply to the Tire Pressure
Control System.
If the system is able to generate a sufficient air supply, Code 4P! means
that a leak or restriction exists in an air passage. The components that
may contain a restricted or leaking air passage include:
• Wheel valve air filters
• Pneumatic Control Unit (PCU) vent port restriction
• Air supply lines
• Wheel valve exhaust port (deflate mode only)
To correctly diagnose the faulty component, connect the Diagnostic
Tool (see Section 5 for test equipment and descriptions) and follow the
procedure in the 3P! troubleshooting tree.
See “Troubleshooting Tips” on page 20 for general guidelines on system
diagnostics.
Code:
4P!
Type:
Channel Between Modes