C0245
DTC C0245
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC C0245 00
- Wheel Speed Sensor Frequency
Diagnostic Fault Information
Circuit/System Description
Each wheel speed sensor receives ignition voltage through the signal high circuit from the electronic brake control module. Wheel speeds are detected by active wheel speed sensors and encoder rings. The magnetic encoder rings consists of multiple north and south pole pairs surrounding the outer circumference. When the encoder ring rotates and passes by the wheel speed sensor; it generates a sign wave in the wheel speed sensor. The sensor converts the signal to a digital square wave; the square wave values switch between 7mA (Low) and 14mA (High) DC current. As the wheel spins, the module uses the frequency of the square wave signal to calculate the wheel speed.
Conditions for Running the DTC
* DTC C0035, C0040, C0045, or C0050 is not present.
* Vehicle speed is between 20 km/h (13 MPH) and 50 km/h (31 MPH).
* While driving a curve with a yaw-rate of 3° per second for greater than 9 seconds.
Conditions for Setting the DTC
* A short to voltage on any one of the wheel speed sensor ignition circuits.
* A electrical magnetic interference with the wheel speed sensor harness.
* Difference between the fastest and slowest wheel speed is greater than 6 km/h (4 MPH).
* If two or more wheel speed sensor faults are detected without the ABS warning lamp being turned ON.
* The electronic brake control module cannot determine a specific wheel speed sensor signal because of electrical interference.
Action Taken When the DTC Sets
* The ABS indicator turns ON.
* The stability control indicator turns ON.
* The traction control Off indicator turns ON.
* The stability control Off indicator turns ON.
* The driver information center displays the Service StabiliTrak message.
* The electronic brake control module disables the ABS, traction control, and stability control for the duration of the ignition cycle.
Conditions for Clearing the DTC
* When the condition for setting the DTC is no longer present.
* The history DTC will clear after 40 consecutive fault-free ignition cycles have occurred.
Note: During normal diagnostic and/or repair verification technicians may find that the ABS, Traction Control and/or Stabilitrak indicators may be ON with NO DTCs displayed by the electronic brake control module. Do not replace the electronic brake control module for this condition.
If the ABS, Traction Control and/or Stabilitrak telltales are ON with no DTCs set, perform the following steps:
1. Remove the key from the ignition, open and close the driver's door to turn off retained accessory power (RAP), and wait 60 seconds.
2. Ignition ON, if the ABS, Traction Control and/or Stabilitrak telltales are still illuminated, operate the vehicle at speeds greater than 15 km/h (10 mph) to complete the self test. The electronic brake control module should request all telltale indicators to turn OFF.
3. If the telltales remain ON with no DTCs set after the drive cycle, disconnect the battery for at least 60 seconds then reconnect the battery.
4. Operate the vehicle at speeds greater than 40 km/h (25 mph), the electronic brake control module should request all telltale indicators to turn OFF.
Diagnostic Aids
* Do not use a magnet to clean the encoder ring.
* Check for electrical magnetic interference with the wheel speed sensor harness.
* If two 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.
Reference Information
Schematic Reference
Antilock Brake System Schematics [1][2]Antilock Brakes / Traction Control Systems
Connector End View Reference
Component Connector End Views Fuel Pump and Level Sensor Assembly
Description and Operation
ABS Description and Operation (Without F55) ABS Description and Operation (Without F55)ABS Description and Operation (With F55) ABS Description and Operation (With F55)
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Verify that all tires have the proper air pressure.
• If not the proper air pressure
Adjust all tire air pressures to the stated cold air
pressure as identified on the tire placard or specification.
• If the proper air pressure
2. Verify that all tires are of uniform size and matching brand.
• If not of uniform size or matching brand
1. Replace the mis-sized or non-matching brand tire.
2. Ignition ON.
3. Verify the DTC does not set while operating the vehicle within the Conditions for Running the DTC.
• If the DTC set, replace the K17 electronic brake control module.
• If the DTC does not set
4. All OK.
• If all tires are of uniform size and matching brand
3. Refer to Circuit/System Testing.
Circuit/System Testing
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the K17 electronic brake control module, ignition ON.
2. Test for less than 1 V between the K17 electronic brake control module harness connector terminals listed below and ground:
* B5LF left front wheel speed sensor - terminal 21
* B5RF right front wheel speed sensor - terminal 18
* B5LR left rear wheel speed sensor - terminal 33
* B5RR right rear wheel speed sensor - terminal 19
• If 1 V or greater
Repair the short to voltage on the circuit.
• If less than 1 V
3. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
Control Module References Control Module References for electronic brake control module replacement, programming and setup