URAL Motorcycles 4320M, Operation Manual, Page: 136 / 321

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Special ABS mode should not be used on roads as truck stability and steerability can be
lost.
4.5.5.3 ABS Operation, Maintenance and Test
When switching on (when the starter is turned to the position “DEVICES”) “Tractor
ABS” indicator 2 switches on (see Figure 114) for conventional cab trucks and “Tractor ABS”
indicator 34 (see Figure 29) for cabover trucks is on, automatic test of the electronic unit and elec-
trical chains of the devices, modulators and switching units is performed, after test completion the
lamp will fade, if there are no failures.
1-ABS test switch; 2-”Tractor ABS” indicator
Figure 114 - ABS Control Unit
If the memory contains failures, the lamp will fade out, if they are eliminated and the
truck reaches 5-7 km/h speed. When there is a failure in the system or in electrical chains of one
component (sensors, modulators) or control circuits, “Tractor ABS” indicator 2 switches on (see
Figure 114) for conventional cab trucks and “Tractor ABS” indicator 34 (see Figure 29) for
cabover trucks is on. Herein, it is possible to switch off the corresponding ABS circuit, and the
brake system will work in ordinary mode (without ABS mode).
The system does not require special maintenance, except cross check of functioning
and check of ABS sensors installation when adjusting or replacing bearings in wheel assem-
blies or replacing brake linings.
4.5.5.4 ABS Test
System condition can be determined through diagnostic equipment or with blink codes
(light). Blink codes check is simple and does not require dedicated equipment.
Blink code test is used to detect failures that ECU discovered.
Before blink code test is is necessary to start up the ignition (connect ABS to voltage).
During the test ABS is not functioning! After start up the ignition wait 1 sec at least
before pushing test button.
4.5.5.5 Knorr Bremze ABS Blink Code Test
Electrical schemes of components connection to Knorr Bremze control unit are shown in
Figure 115.