Buick Regal: DTC C0242
Diagnostic Instructions
- Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
- Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
- Diagnostic Procedure Instructions provides an overview of each
diagnostic category.
DTC Descriptor
DTC C0242
Powertrain Control Module Indicated Traction Control
For symptom byte information refer to Symptom Byte List.
Circuit/System Description
The electronic brake control module and the engine control module
simultaneously control the traction
control. The electronic brake control module sends a serial data message to the
engine control module
requesting torque reduction. When certain engine control module DTCs are set,
the engine control
module will not be able to perform the torque reduction for traction control. A
serial data message is
sent to the electronic brake control module indicating that traction control is
not allowed.
Conditions for Running the DTC
Engine running
Conditions for Setting the DTC
The engine control module detects a fault that prevents it from performing a
traction control function
and sends a serial data message to the electronic brake control module
indicating that torque reduction is
not allowed.
Action Taken When the DTC Sets
The electronic brake control module sends a serial data message to illuminate
the appropriate
warning/indicator message.
Conditions for Clearing the DTC
- The condition for the DTC is no longer present.
- The electronic brake control module clears the history DTC when a
current DTC is not detected in
100 consecutive drive cycles.
Diagnostic Aids
- Inspect for proper transmission operation.
- Inspect the exhaust system for a possible restriction.
- Inspect for lack of engine power, hesitation, stumble or rough idle.
- Some intermittent communication concerns may be caused by fretting
corrosion on the serial data
circuit terminals. Inspect all connectors at the control module that set the
communication DTC,
the control module that the communication DTC was set against, and any
inline harness
connectors between the two control modules. Do not replace a control module
based only on
fretting corrosion.
Reference Information
Schematic Reference
Antilock Brake System Wiring Schematics
Connector End View Reference
Component Connector End View Index
Description and Operation
ABS Description and Operation
Electrical Information Reference
- Circuit Testing
- Connector Repairs
- Testing for Intermittent Conditions and Poor Connections
- Wiring Repairs
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify that no other DTCs are set except for C0242.
- If any other DTCs are set
Refer to the Diagnostic Trouble Code (DTC) List - Vehicle.
- Go to next step: If no other DTCs are set
3. Replace the K20 Engine Control Module.
4. Verify that DTC C0242 does not set while operating the vehicle within the
Conditions for
Running the DTC.
Replace the K17 Electronic Brake Control Module.
- Go to next step: If DTC does not set
5. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
Control Module References for electronic brake control module or engine control
module replacement,
programming and setup.
DTC C0245
Diagnostic Instructions
- Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
- Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
- Diagnostic Procedure Instructions provides an overview of each
diagnostic category.
DTC Descriptor
DTC C0245
Wheel Speed Sensor Frequency
For symptom byte information refer to Symptom Byte List.
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 3º per second for greater
than 9 s.
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 traction control Off indicator turns ON.
- The stability control Off indicator turns ON.
- The traction/stability control indicator turns ON.
- The driver information center displays the Service StabiliTrak message.
- The electronic brake control module disables the ABS, the traction
control, and the 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.
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 Wiring Schematics
Connector End View Reference
Component Connector End View Index
Description and Operation
ABS Description and Operation
Electrical Information Reference
- Circuit Testing
- Connector Repairs
- Testing for Intermittent Conditions and Poor Connections
- Wiring Repairs
Scan Tool Reference
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.
- Go to next step: 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
- Replace the mis-sized or non-matching brand tire.
- Ignition ON.
- 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.
- Go to next step: If the DTC does not set
- All OK.
- Go to next step: 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 7
- B5RF Right Front Wheel Speed Sensor - terminal 26
- B5LR Left Rear Wheel Speed Sensor - terminal 23
- B5RR Right Rear Wheel Speed Sensor - terminal 37
- If 1 V or greater
Repair the short to voltage on the circuit.
- Go to next step: If less than 1 V
3. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
Control Module References for Electronic Brake Control Module replacement,
programming and setup
READ NEXT:
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
SEE MORE:
Removal Procedure
WARNING: Brake Dust Warning.
WARNING: Brake Fluid Irritant Warning.
CAUTION: Brake Fluid Effects on Paint and Electrical Components
Caution.
NOTE: Always replace disc brake pads in axle sets.
1. Inspect the fluid level in the brake master cylinder reservoir.
If the brake fluid l
Buick encourages customers to call
the toll-free number for assistance.
However, if a customer wishes to
write or e-mail Buick, the letter
should be addressed to:
United States and Puerto Rico
Buick Customer Assistance Center
P.O. Box 33136
Detroit, MI 48232-5136
www.Buick.com
1-800-521-7300
1-800-