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f:tec\manuals\Service\SERVICEv5.indd - V6-0615
SERVICE MANUAL
TIREBOSS
TM
Tire Pressure Control
“VALVE NO POWER” ALERT
Valve Circuit Board 1393-01
This alert appears on the Cab Controller display to indicate an existing problem related to the system Valve Controller
circuit board power.
Notes:
i. In the following descriptions, “RLY” is Relay and “VPS” is Valve Power Supply.
ii. In the following description and trouble shooting sequence, when the word voltage is used, the meaning is a
nominal 11-15 volts DC as measured against ground.
iii. When checking for voltages at RLY or VPS, it is important to monitor the voltage at the respective terminal
for at least 5-10 seconds because when the Valve No Power fault occurs, the Cab Controller automatically
cycles the voltage to RLY On and Off. Therefore, checking for voltage just momentarily may provide inaccurate
information.
iv. An intermittent voltage condition, such as that caused by a loose wire connection on the VPS circuit, will cause
the Cab Controller to display a “Valve No Power” alert.
v. An intermittent voltage condition on the RLY circuit will cause the Cab Controller to fi rst display a “Valve No
Power” alert followed by a “Com Error” alert.
vi. Refer to drawing on page 1-5 for location of Cab Controller components.
vii. Refer to drawing on page 1-7 for location of Valve Controller circuit board components.
Short description of the valve power circuit operation:
When the Cab Controller is On, voltage is supplied from the Cab Controller to the Valve Controller through the (Orange)
RLY wire in the Power/Data cable.
The RLY circuit begins at the Cab Controller circuit board connector J1-Pin 4 and ends at the Valve Controller circuit
board connector strip J2 at terminal 14, marked RLY.
Voltage present at RLY will energize relay 1CR on the Valve Controller circuit board. When 1CR is energized, a voltage
signal is supplied back to the Cab Controller through the (Green) VPS wire in the Power/Data cable. Voltage on the
VPS wire indicates to the Cab Controller that the Valve Controller has power.
The VPS circuit begins on the Valve Controller circuit board at connector strip J2 at terminal 12, marked VPS and ends
at connector J1-Pin 3 on the Cab Controller circuit board.
With the Cab Controller “On”, voltage should be present in the RLY circuit as well as the VPS circuit. The absence of
voltage in EITHER the RLY or VPS circuit will trigger the “Valve No Power” alert.
Trouble shooting a “Valve No Power” fault:
Perform the following trouble shooting steps, in the order listed, to isolate the cause of the fault.
1. With the Cab Controller turned On, remove the Valve Controller cover and determine that wires at
terminals RLY (Orange) and VPS (Green) are tight and secure.
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