Spicer TPCS Troubleshooting Guide: Older Systems (ECU's w_Dual Connectors) - Manual (Page 30)

30
Troubleshooting
Code Description
Codes 7C! through 12C! indicate an electrical fault in the Pressure
Control Unit (PCU). System operation is disabled when these faults are
detected.
The system shuts down in a fail­safe mode and turns off the relay power
to the solenoids.
The troubleshooting tree first tests internal solenoid circuitry. Resistance
outside the specified range of 7 to 25 ohms indicates a defective
solenoid. Succeeding steps check continuity of the wire harness circuits
between the Pneumatic Control Unit and the Electronic Control Unit
(ECU). If the problem can be traced to a faulty circuit or connector, make
the necessary repairs. If the troubleshooting routine leads to a problem
with the solenoid itself, the Pneumatic Control Unit must be repaired
or replaced. If both the solenoid and the circuitry check out OK, the
Electronic Control Unit is faulty.
See “Troubleshooting Tips” on page 20 for general guidelines on system
diagnostics.
Code:
7C!, 8C!, 9C!, 10C!, 11C!, 12C!
Type:
Solenoids
7C = Steer
8C = Drive
9C = Trailer
10C = Supply
11C = Deflate
12C = Control