Spicer TPCS Troubleshooting Guide: Older Systems (ECU's w_Dual Connectors) - Manual (Page 34)

34
Troubleshooting
Code Description
Code 1P! indicates inadequate vacuum in the Pneu matic Control Unit
(PCU) prior to channel selection or failure to sustain a vacuum in a control
line following channel selection. Code 1P! will be set when the nominal
vacuum of 26” Hg drops to 20” Hg. Code 1P! can be generated by one
channel or multiple channels.
When a deflate is requested, the system first shuts off all the channel
control lines and generates a vacuum in the Pneumatic Control Unit
alone. A failure to generate this vacuum will result in a 1P!.
Once the vacuum has been established in the Pneu matic Control Unit,
the desired channel control line(s) are opened and a vacuum is generated
in them. If the system fails to generate a vacuum in the control lines after
two attempts, it will log a 1P! fault.
Note: If a fault occurs on any channel, deflation is disabled for all
channels.
Code 1P! can be caused by:
• Faulty Pneumatic Control Unit
• Plugged or restricted Pneumatic Control Unit vent line
• Line leak
• Air seal or oil lip seal leaks.
To correctly diagnose the faulty component, connect the Diagnostic
Tool (see Section 5 for test equipment and descriptions) and follow the
procedure in the 1P! troubleshooting tree.
See “Troubleshooting Tips” on page 20 for general guidelines on system
diagnostics.
Code:
1P!
Type:
No Deflate Signal