WABCO iABS 2S/1M Standard Maintenance Manual page 144

Troubleshooting
Condition
Experienced
Optional Lift
Axle LED
Indicator
Lamp Stays
on Faintly
Pressure
Switch Test
Pressure
Sensor Test
144
Action to Take
Ensure that the correct
indication lamp type is
activated.
Check light output cable
integrity.
Inspect indicator lamp and
cable.
Inspect indicator light wiring.
Inspect indicator light.
Check light output cable
integrity.
Check pressure switch 431 700
002 0 functionality.
Test the pressure sensor 441
044 106 0 functionality.
s
Troubleshooting Detail
While entering the parameters to program the iABS
with Auto Lift Axle function, ensure that Lift Axle Status
Lamp is either LED or Incandescent Lamp.
Using a volt/ohm meter, check for a shorted or open
circuit on lift axle indication lamp cable 449 827 XXX 0.
Refer to Figure 9.6.
If damaged, replace the LED lamp with a load-resistor
LED or incandescent lamp.
Ensure the load-resistor LED lamp is wired correctly.
Make sure the brown wire is connected to ground and
the red wire hooked to power.
When using an LED lamp, ensure the LED assembly
has a load resistor. When using an incandescent light,
ensure that a 12v light is being used.
Using a volt/ohm meter, check for a shorted or open
circuit on lift axle indicator light cable 449 827 XXX 0.
Refer to Figure 9.6.
Refer to Figure 9.5 for the connector diagram of
pressure switch 431 700 002 0. Use regulated shop
air and an ohm meter to check the functionality of the
switch. With greater than 70 psi (and less than 100 psi)
applied to the switch, pins 1 and 2 resistance reading
should show infi nity. With less than 70 psi applied to
the switch, pins 1 and 2 resistance reading should
show less than 1 ohm.
Refer to Figure 9.212 for the construction of a Auto
Lift Axle Test Rig. Attach regulated shop air to the
pneumatic connector of pressure switch 441 044
106 0. Increase pressure so that it exceeds the
parameterized lower axle threshold and the axle should
deploy. Decrease pressure so that it drops below the
parameterized threshold to raise the axle and the axle
should rise.