This task covers:
a. Operating Test
Trailer parked on level ground, brakes engaged.
Tool kit, mechanics general
and wheels chocked.
Apply 12 volt DC power to the ABS.
The ECU/dual modulator valve assembly should click four times.
If the ABS indicator lamp comes on for three seconds and then goes out, this indicates a
proper installation. The Operating Test is complete.
If the ABS indicator lamp comes on and stays on, check the sensor installation by removing
power from the ABS and raising the sensed wheels so they may be rotated.
Apply emergency air to fill the air tanks and release the spring brakes so that the wheels
may be rotated.
Repeat Steps (1) and (2).
Rotate each sensed wheel, one at a time and at a rate of 1/2 revolution per second. This
rate equals a wheel speed of approximately 4 mph (7 kph). If the ABS indicator lamp goes
out and stays out, a proper installation is indicated and the Operating Test is complete.
If the ABS lamp does not go out, there is a sensor gap problem or hardware fault. Adjust
the sensor gap and, if necessary, perform a fault code check (Ref. Step 11).