2010 Cadillac CTS Sedan AWD V6-3.6L Page 660
* An erratic signal output of the wheel speed sensor is detected 3 times in 200 milliseconds.
* The EBCM detects a change in wheel speed that exceeds 20 km/h (12 mph) between two 10 millisecond wheel speed samples. This must be
detected 3 times in 200 milliseconds.
* A missing wheel speed sensor signal.
Actions Taken when the DTC Sets
* The EBCM disables the antilock brake system (ABS), traction control and StabiliTrak for the duration of the ignition cycle.
* A driver information center message and/or a warning indicator may be displayed.
Conditions for Clearing the DTC
* The condition for the DTC is no longer present.
* Operate the vehicle at speeds greater than 15 km/h (10 mph) to complete the self test, and the EBCM will turn off the ABS indicator.
* The EBCM clears the history DTC when a current DTC is not detected in 40 consecutive drive cycles.
Diagnostic Aids
* Inspect the back of the wheel bearing on the encoder surface for metal debris that could cause an erratic reading with the sensor. Do not use a
magnet to clean the debris, or damage to the encoder ring may occur.
* If 2 or more wheel speed sensors are inoperative diagnose each wheel speed sensor individually.
If the customer comments that the ABS indicator is ON only during moist environmental conditions: rain, snow, vehicle wash, etc., inspect the
wheel speed sensor wiring for signs of water intrusion. If the DTC is not current, clear all DTCs and simulate the effects of water intrusion by using
the following procedure:
1. Spray the suspected area with a 5 percent saltwater solution. To create a 5 percent saltwater solution, add 2 teaspoons of salt to 8 fl oz of
water (10 g of salt to 200 ml of water).
2. Test drive the vehicle over various road surfaces: bumps, turns, etc., above 40 km/h (25 mph) for at least 30 seconds.
3. Rinse the area thoroughly when completed.
Reference Information
Schematic Reference
Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical Diagrams)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
ABS Description and Operation (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit
Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Wiring Repairs/Wiring Repairs)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Verification
Observe the scan tool Wheel Speed Sensor parameter. The reading should be the same speed on all sensors when driving in a straight line at a
speed greater than 20 km/h (13 mph).
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the EBCM.
2. Ignition ON, test for less than 1 V between the ignition voltage circuit terminal of the appropriate sensor listed below and ground.
* Left front sensor circuit terminal 29
* Right front sensor circuit terminal 6
* Left rear sensor circuit terminal 5
* Right rear sensor circuit terminal 2
瀚慖f greater than the specified range, test the ignition voltage circuit for a short to voltage.
