
3 Diagnostics, Troubleshooting and Testing
34
Meritor WABCO Maintenance Manual MM-0112 (Revised 05-13)
NOTE: For correct sensor operation, there must be a jumper wire on
the harness side across either Pin 2 to Pin 3 so terminating resistor
is connected as shown in Figure 3.39.
Figure 3.38
Figure 3.39
Figure 3.40
Figure 3.41
ECU Circuit Testing
Electrical Checks
앫 Verify vehicle batteries, charging system and fuses are in good
working condition.
앫 Load test battery and ignition circuits to ground at the ECU
harness using a 2-4 amp sealed lamp and verify lamp does not
flicker and it is on steady.
Location Measurement
Meritor Wabco SAS terminating
resistor
Approximately 180 ohms
CAN High Voltage 2.5-5.0V
CAN Low Voltage 0.1-2.4V
Voltage Supply to Ground 8.0-16.0V
ESC CAN-High to ESC CAN-Low Approximately 90 ohms
SAS harness jumper (Pin 2 to
Pin 4 or Pin 2 to Pin 3)
Continuity
ESC CAN-High or CAN-Low to
Power or Ground
No continuity
With ESC, SAS and ECU
unplugged harness by itself for
battery voltage or ground
No continuity
Figure 3.38
Figure 3.39
4010631a
4
CAN-HIGH
180 OHM
CAN-LOW
+U-BATT
GND
3
2
1
5
6
STEERING ANGLE SENSOR
Figure 3.40
Pin Circuit
1CAN-Low
2 Terminating Resistor
3CAN-High
4CAN-High
5Power
6 Ground
Figure 3.41
4007216a
STEERING ANGLE SENSOR CONNECTOR
123456
4007215a
CAB MOUNT ECU:
LOOKING INTO WIRE
HARNESS CONNECTOR
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
X4
FRAME MOUNT ECU
WITH ESC:
LOOKING INTO WIRE
HARNESS CONNECTOR
12
3456
71012 911 8
131618 1517 14
X2-GREEN
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