mm28 Anti Lock Braking Systems ABS for Trucks, Tractors, and Buses C Version

3 Troubleshooting

Testing The locations of sensors and valves are illustrated in Figure 3.4, Figure 3.5, Figure 3.6, Figure 3.7, Figure 3.8 and Figure 3.9. Most vehicles with spring suspension have sensors on forward-rear axle. Most vehicles with air suspension have sensors on rear-rear axle. NOTE: Liftable axles are always the third axle with ABS.

Figure 3.4

TOOTH WHEEL

SENSOR

PNEUMATIC ELECTRIC

TOOTH WHEEL

SENSOR ECU

1

2

1

2

ABS MODULATOR VALVES

ABS MODULATOR VALVES

1

2 3

1

2 3

SENSOR

SENSOR

TOOTH WHEEL

TOOTH WHEEL

1

2 3

1000422a

Figure 3.4

Figure 3.5

TOOTH WHEEL

TOOTH WHEEL

PNEUMATIC ELECTRIC

SENSOR

TOOTH WHEEL

6x2

SENSOR ECU

1

2 3

6x4 6x6

1

2 3

SENSOR

ABS MODULATOR VALVES

ABS MODULATOR VALVES

6x4 6x2

1

2 3

SENSOR

SENSOR

SENSOR

TOOTH WHEEL

TOOTH WHEEL

TOOTH WHEEL

1000423a

Figure 3.5

16 WABCO Maintenance Manual MM-28 (Revised 03.2020)