Subaru C0071 DTC: Steering Angle Sensor Communication Malfunction
The Subaru C0071 Diagnostic Trouble Code (DTC) is a chassis-related fault code associated with the Anti-lock Braking System (ABS) and Vehicle Dynamics Control (VDC). On many Subaru models, C0071 indicates a malfunction involving the Steering Angle Sensor (SAS), including an invalid signal, communication fault, or a sensor that requires calibration. Since the steering angle sensor is a critical input for the ABS, Traction Control System (TCS), and Electronic Stability Control (ESC), a failure can reduce vehicle stability and disable several safety functions. This guide from OBDSpark explains the symptoms, causes, diagnostic procedures, live data, typical sensor specifications, oscilloscope waveforms, repair costs, and professional diagnostic tips.
What Does Subaru C0071 Mean?
Subaru DTC C0071 indicates that the ABS/VDC control module has detected an abnormal Steering Angle Sensor signal or a communication/calibration problem. The steering angle sensor continuously reports the driver's steering input to the ABS and stability control system. If the signal is incorrect, missing, or outside the expected range, the control module disables certain stability functions and stores DTC C0071.
Symptoms
- ABS warning light illuminated.
- Vehicle Dynamics Control (VDC) warning light ON.
- Traction Control disabled.
- Hill Start Assist may become unavailable.
- Cruise control may stop operating.
- Steering angle value incorrect in live data.
- Additional ABS or CAN communication codes may be stored.
Common Causes
- Faulty Steering Angle Sensor.
- Steering Angle Sensor calibration required.
- Damaged clock spring.
- Open or short circuit in the sensor wiring.
- Loose, corroded, or damaged connector.
- CAN communication fault.
- Low system voltage.
- Faulty ABS/VDC control module (rare).
Typical Diagnostic Flow
Typical Steering Angle Sensor Specifications
| Item | Typical Specification |
|---|---|
| Sensor Type | Steering Angle Sensor (SAS) |
| Location | Behind the steering wheel inside the clock spring assembly |
| Pin Count | Typically 4–6 pins |
| Power Supply | Typically 5V or 12V |
| Signal Type | CAN, LIN, PWM or Analog (varies) |
| Operating Range | Approximately ±720° to ±900° |
| Ground | Dedicated sensor ground |
| Typical Wire Colors | Black = Ground, Red/Pink = Power, Green/White = CAN High, Green/Blue = CAN Low (varies) |
Note: Pin configuration, voltage, communication protocol, and wire colors vary depending on the Subaru model and production year. Always consult the factory wiring diagram before performing electrical tests.
Typical Live Data
| Parameter | Typical Value |
|---|---|
| Steering Angle | 0° ±5° (Steering Centered) |
| Supply Voltage | 5V or 12V |
| Sensor Status | Valid |
| Calibration Status | Completed |
| CAN Communication | Normal |
Typical Oscilloscope Signal Patterns
Stable waveform with consistent pulse spacing and amplitude.
Missing pulses or unstable communication caused by loose wiring, damaged clock spring, or connector faults.
No valid output signal. Possible sensor failure, power loss, or communication fault.
How to Diagnose Subaru C0071
- Connect a professional scan tool and confirm DTC C0071.
- Check for additional ABS, VDC, or CAN communication DTCs.
- View Steering Angle Sensor live data while turning the steering wheel from lock to lock. The value should change smoothly without sudden jumps or dropouts.
- Inspect the Steering Angle Sensor connector for loose terminals, corrosion, or water intrusion.
- Inspect the clock spring for damage or an open circuit.
- Verify the sensor power supply, ground, and communication circuits using a digital multimeter.
- Use an automotive oscilloscope to verify signal quality if an intermittent fault is suspected.
- Perform Steering Angle Sensor calibration using a professional scan tool after repairs or wheel alignment.
- Clear the DTC and perform a road test to confirm the repair.
Common Repair Mistakes
- Replacing the Steering Angle Sensor before performing calibration.
- Ignoring a damaged clock spring.
- Replacing the ABS/VDC module without confirming sensor operation.
- Skipping live data analysis.
- Ignoring low battery voltage or charging system faults.
- Not checking CAN communication.
- Failing to perform a steering angle calibration after wheel alignment or steering repairs.
Recommended Diagnostic Tools
| Tool | Purpose |
|---|---|
| Autel MaxiSYS | Read DTCs, Live Data and SAS Calibration |
| Launch X431 | Advanced ABS/VDC Diagnosis |
| Bosch KTS | OEM-Level Diagnostics |
| Digital Multimeter (DMM) | Power Supply and Ground Testing |
| Automotive Oscilloscope | Signal Waveform Analysis |
Estimated Repair Cost
- Steering Angle Sensor Calibration: $50–150
- Steering Angle Sensor Replacement: $150–600
- Clock Spring Replacement: $200–500
- Wiring Repair: $50–250
- ABS/VDC Module Replacement (Rare): $500–1,500
Related DTCs
Frequently Asked Questions (FAQ)
Can I drive with Subaru C0071?
Yes. Normal braking usually remains available, but the ABS, VDC, and Traction Control systems may not operate correctly. Repairing the fault as soon as possible is recommended.
Does C0071 always mean the Steering Angle Sensor is faulty?
No. The problem may be caused by a calibration issue, damaged clock spring, wiring fault, poor connector contact, or CAN communication problem.
Can a wheel alignment trigger C0071?
Yes. Some Subaru models require Steering Angle Sensor calibration after wheel alignment or steering component replacement.
Can low battery voltage cause C0071?
Yes. Low system voltage may interrupt sensor communication and trigger ABS or VDC-related DTCs.
Always compare Steering Angle Sensor live data with the steering wheel position before replacing any component. In many cases, performing a Steering Angle Sensor calibration resolves C0071 without replacing the sensor.
OEM Service Information
The definition of DTC C0071 is not standardized across all vehicle manufacturers. While many Subaru vehicles use C0071 for a Steering Angle Sensor-related malfunction, other manufacturers may assign a different definition to the same code.
| Manufacturer | Typical Definition |
|---|---|
| Subaru | Steering Angle Sensor communication, signal, or calibration fault. |
| Other Manufacturers | Definition may differ. Always consult the factory service manual. |
Technical Notes
- The Steering Angle Sensor must be centered before calibration.
- After wheel alignment or steering repairs, recalibration may be required.
- Battery voltage below specification may trigger communication faults.
- Always inspect the clock spring before replacing the sensor.
- CAN communication faults can generate additional ABS or VDC DTCs.
Repair Verification
- Clear all stored DTCs.
- Start the engine.
- Confirm the ABS and VDC warning lamps remain OFF.
- Verify Steering Angle Sensor live data changes smoothly from lock to lock.
- Perform Steering Angle Sensor calibration if required.
- Road test the vehicle at different speeds.
- Recheck for pending or stored DTCs.
Conclusion
Subaru DTC C0071 is commonly associated with a Steering Angle Sensor communication or calibration problem that can affect the ABS, Traction Control, and Vehicle Dynamics Control systems. In many cases, the issue is caused by a sensor calibration problem, damaged clock spring, wiring fault, or poor electrical connection rather than a failed sensor. Following a systematic diagnostic procedure with professional scan tools, live data analysis, and proper calibration helps identify the root cause and prevents unnecessary parts replacement.