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Tab le 8 – Troubles and methods of trouble-shooting for Wabco
Error code
Method of trouble-shooting
2-…
Check the modulator cable. Wire breakage or their insulation damage is possible.
3-…
Low value of sensor signal amplitude. Check bearing and toothed rotor runout, move
the sensor closer to the rotor. Check sensor cable continuity and contact closeness in
plug-and-sockets.
4-…
Check sensor cable continuity
5-…
Check sensor cable. Check toothed rotor for absence of damages. Wheels diameters or
toothed rotors teeth number may be different
.
6-…
Check toothed rotor for absence of damages, Runout, for all teeth availability. Change
faulty rotor if necessary.
8 - 1
Check power supply cable and safety fuse. Low voltage in the truck power network.
8 - 2
Check voltage on generator and accumulator terminals
8 - 3
Replace the control unit if the error is repeated.
8 - 4
Electronic control unit doesn't correspond to the specified number of wheel sensors and
modulators. Replace the control unit.
8 - 5
Check “grounding” of the electronic control unit and modulators.
5.5.7 Auxiliary brake system
The auxiliary compression type brake reduces the vehicle speed on long downgrades.
Braking deceleration is achieved by creating back pressure in the exhaust gas pipes of the engine
when they are overlapped by shutters.
The brake consists of the case 3 (Fig. 105) and the shutter. The shutter is driven by the air
cylinder 1 fixed by the bracket on the case of the auxiliary brake.
In case it is necessary to decelerate, press the button of the auxiliary brake pneumatic
control valve located on the cab floor. Compressed air is delivered to the air cylinder, the piston
moves closing the shutter.
Simultaneously the signal is transferred to the trailer brakes drive and the trailer is braked
slightly.
1-Air cylinder; 2-drive rod fork; 3-case; 4-
shutter; 5-shutter shaft lever; 6-key; 7-pin; 8-
cotter pin
Figure 105 – Auxiliary brake
