29
Troubleshooting and Testing
4.10
Steering Angle Sensor (SAS) Testing
Electrical Checks
The following tests are for WABCO SAS Only.
Disconnect SAS and check terminating resistance across Pin 1 and Pin 2 of the SAS.
For the following checks, all the ECU and ESC module connectors must be plugged in as the ECU
provides all voltage, ground and CAN communications.
Take measurements at the SAS harness connector side.
•
Check Key On CAN Low voltage on Pin 1.
•
Check Key On CAN High voltage on Pin 4.
•
Check Key On Voltage Supply on Pin 5.
•
Check Key Off resistance across CAN low Pin 1 and CAN High Pin 4.
Location
Measurement
WABCO SAS terminating
resistor on sensor
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 ohm
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 (with ECU,
ESC Module and SAS
unplugged)
No continuity
For correct sensor operation, there must be a jumper wire on the harness side across either
Pin 2 to Pin 3 or Pin 4 so terminating resistor is connected as shown below.
4006873a
