Introduction:
The diagnostic trouble code (DTC) C0473 indicates a fault in the steering handwheel speed sensor circuit, specifically that the signal voltage is higher than expected. This sensor is crucial for systems like Electronic Power Steering (EPS) and stability control, providing vital information about the driver's steering input. When the signal is excessively high, these systems might not function correctly, leading to compromised steering performance and potential safety concerns.
Comprehensive Table: C0473 - Steering Handwheel Speed Sensor Signal V High
| Attribute | Description | Potential Impact |
|---|---|---|
| DTC Code | C0473 | Indicates a high voltage signal from the steering handwheel speed sensor. |
| Sensor Function | Measures the rotational speed and direction of the steering wheel. This data is used by the EPS, stability control (ESC), and other vehicle systems. | Incorrect or absent data can lead to EPS malfunction, ESC disengagement or erratic behavior, and compromised vehicle handling. |
| Normal Voltage Range | Typically between 0.5V and 4.5V, varying based on sensor type and vehicle manufacturer. Consult the specific vehicle service manual for exact specifications. | A voltage outside this range (specifically higher) triggers the C0473 code. |
| Possible Causes | Short to voltage in the sensor wiring, faulty sensor, wiring harness damage, ECM/BCM malfunction, poor ground connection, corrosion in connectors, high resistance in the circuit. | Erratic steering assist, loss of power steering, ESC system failure, potential safety hazards. |
| Symptoms | Stiff or no power steering, erratic steering assist, stability control system malfunction light illuminated, ABS light illuminated, difficulty steering, vehicle pulling to one side, warning messages on the dashboard. | Reduced driver control, increased risk of accidents, compromised vehicle safety. |
| Affected Systems | Electronic Power Steering (EPS), Electronic Stability Control (ESC), Anti-lock Braking System (ABS), Traction Control System (TCS), Vehicle Stability Assist (VSA). | These systems rely on accurate steering input data. A faulty sensor can disable or impair their function. |
| Diagnostic Tools | OBD-II scanner, multimeter, oscilloscope, wiring diagram, vehicle-specific diagnostic software. | These tools are essential for identifying the root cause of the problem. |
| Troubleshooting Steps | Check wiring for shorts to voltage, inspect sensor for damage, verify sensor voltage and ground, test wiring continuity, examine connectors for corrosion, check ECM/BCM for proper operation, consult vehicle-specific service manual. | Systematic troubleshooting is crucial for accurate diagnosis and repair. |
| Common Fixes | Repair or replace damaged wiring, replace faulty sensor, clean or replace corroded connectors, repair or replace faulty ECM/BCM (rare), improve ground connection, ensure proper sensor alignment. | Correcting the underlying issue will restore proper sensor function and system performance. |
| Related DTCs | C0472 (Steering Handwheel Speed Sensor Signal Low), C0475 (Steering Angle Sensor Circuit Malfunction), other codes related to EPS, ESC, and ABS systems. | These codes can provide additional clues about the problem. |
| Sensor Type | Typically a Hall-effect sensor or a variable reluctance sensor. | Understanding the sensor type is important for proper testing and diagnosis. |
| Location | Integrated within the steering column or steering gear assembly. | Accessibility varies depending on the vehicle model. |
| Calibration Requirements | Some vehicles may require steering angle sensor calibration after replacing the sensor or performing certain repairs. | Failure to calibrate can lead to incorrect system operation. |
| Wiring Color Codes (Example) | Varies by manufacturer. Common colors include: Power (Red/White), Ground (Black), Signal (Green/Yellow). Always refer to the vehicle-specific wiring diagram. | Incorrect wiring can damage the sensor or the vehicle's electrical system. |
| Potential for Intermittent Issues | Yes. Loose connections, temperature changes, and vibration can cause intermittent sensor failures. | Intermittent issues can be challenging to diagnose. |
| Impact on Fuel Efficiency | Indirectly. If the EPS system is malfunctioning, it can increase the load on the engine, slightly decreasing fuel efficiency. | The primary concern is safety and vehicle handling, not fuel economy. |
| Importance of OEM Parts | Recommended. OEM sensors are designed to meet the vehicle's specific requirements and ensure proper system integration. | Aftermarket sensors may not meet the required specifications. |
| ECM/BCM Programming Considerations | In some cases, ECM/BCM programming may be required after replacing the sensor, especially if the sensor is integrated with the control module. | Proper programming ensures that the new sensor is correctly recognized by the vehicle's systems. |
| Effect of Aftermarket Steering Wheels | If an aftermarket steering wheel is installed incorrectly, it can damage the sensor or its wiring, leading to the C0473 code. | Professional installation is recommended for aftermarket steering wheels. |
| Impact of Wheel Alignment | Although not directly related, severe wheel misalignment can put extra stress on the steering system, potentially contributing to sensor failure over time. | Maintaining proper wheel alignment is important for overall vehicle health. |
| Environmental Factors | Extreme temperatures, humidity, and road salt can accelerate corrosion and damage to the sensor and its wiring. | Protecting the sensor and wiring from the elements can help prevent failures. |
| Testing with Oscilloscope | An oscilloscope can be used to visualize the sensor's output signal and identify any anomalies, such as signal dropouts or excessive noise. | Oscilloscope testing can provide more detailed information than a multimeter alone. |
| Ground Circuit Resistance | A high resistance in the ground circuit can cause the sensor signal to be inaccurate. Ideally, the ground resistance should be close to zero ohms. | Checking and cleaning the ground connection is an important troubleshooting step. |
| Shielded Wiring | Some vehicles use shielded wiring for the steering handwheel speed sensor to minimize interference. Damage to the shielding can cause the sensor signal to be corrupted. | Inspecting the shielding for damage is crucial. |
| Impact on Adaptive Cruise Control (ACC) | In vehicles equipped with ACC, a faulty steering handwheel speed sensor can affect the system's ability to maintain lane position. | The ACC system relies on accurate steering input data. |
| Impact on Lane Departure Warning (LDW) | Similar to ACC, a faulty sensor can impair the functionality of the LDW system. | The LDW system also needs accurate steering input data. |
Detailed Explanations:
DTC Code: This code is a standardized identifier that your vehicle's computer uses to report a specific problem. In this case, C0473 means the steering handwheel speed sensor is sending a voltage signal that is too high.
Sensor Function: The steering handwheel speed sensor detects how fast and in what direction you're turning the steering wheel. This information is crucial for systems like EPS, ESC, and other driver-assistance features.
Normal Voltage Range: The normal voltage range varies by vehicle. A typical range is 0.5V to 4.5V, but you should always consult your vehicle's service manual for the exact specifications. A voltage significantly higher than the upper limit of this range will trigger the C0473 code.
Possible Causes: A high voltage signal can be caused by several factors, including a short to voltage in the wiring, a faulty sensor, damaged wiring, ECM/BCM malfunction (less common), or a poor ground connection. Corrosion can also increase resistance in the circuit, mimicking a high voltage situation.
Symptoms: Common symptoms include stiff or erratic power steering, the stability control light turning on, the ABS light turning on, difficulty steering, or the vehicle pulling to one side. Warning messages may also appear on the dashboard.
Affected Systems: This fault primarily affects the EPS, ESC, ABS, and TCS. These systems rely on the steering handwheel speed sensor to function correctly.
Diagnostic Tools: You'll need an OBD-II scanner to read the code, a multimeter to test voltage and resistance, and potentially an oscilloscope to analyze the sensor signal. A wiring diagram specific to your vehicle is also essential.
Troubleshooting Steps: Start by visually inspecting the sensor and its wiring for any damage. Use a multimeter to check the sensor's voltage and ground connections. Test the wiring continuity to identify any breaks or shorts. Finally, examine the connectors for corrosion. Refer to the vehicle-specific service manual for detailed testing procedures.
Common Fixes: The most common fixes include repairing or replacing damaged wiring, replacing the faulty sensor, cleaning or replacing corroded connectors, or improving the ground connection. In rare cases, the ECM/BCM may need to be repaired or replaced.
Related DTCs: Other codes related to the EPS, ESC, and ABS systems, such as C0472 (Steering Handwheel Speed Sensor Signal Low) or C0475 (Steering Angle Sensor Circuit Malfunction), can provide additional clues about the problem.
Sensor Type: The steering handwheel speed sensor is typically a Hall-effect sensor or a variable reluctance sensor. Hall-effect sensors are more common in modern vehicles.
Location: The sensor is usually located within the steering column or steering gear assembly. The exact location varies depending on the vehicle model.
Calibration Requirements: Some vehicles require steering angle sensor calibration after replacing the sensor or performing certain repairs to the steering system. This ensures that the sensor is properly aligned and providing accurate data.
Wiring Color Codes (Example): Wiring color codes vary significantly between manufacturers and even between models of the same manufacturer. Refer to the vehicle-specific wiring diagram. Examples may include: Power (Red/White), Ground (Black), Signal (Green/Yellow).
Potential for Intermittent Issues: Yes, loose connections, temperature fluctuations, and vehicle vibrations can cause intermittent sensor failures, making diagnosis challenging.
Impact on Fuel Efficiency: The impact on fuel efficiency is generally minimal. However, if the EPS system is malfunctioning, it can increase the load on the engine, slightly reducing fuel economy.
Importance of OEM Parts: Using OEM (Original Equipment Manufacturer) sensors is highly recommended. These sensors are designed to meet the vehicle's specific requirements and ensure proper system integration.
ECM/BCM Programming Considerations: In some cases, ECM/BCM programming may be required after replacing the sensor, particularly if the sensor is integrated with the control module.
Effect of Aftermarket Steering Wheels: Incorrect installation of an aftermarket steering wheel can damage the sensor or its wiring, potentially triggering the C0473 code. Professional installation is recommended.
Impact of Wheel Alignment: Although not directly related, severe wheel misalignment can put extra stress on the steering system, potentially contributing to sensor failure over time.
Environmental Factors: Exposure to extreme temperatures, humidity, and road salt can accelerate corrosion and damage to the sensor and its wiring.
Testing with Oscilloscope: An oscilloscope allows you to visualize the sensor's output signal, revealing anomalies like signal dropouts or excessive noise that a multimeter might miss.
Ground Circuit Resistance: High resistance in the ground circuit can distort the sensor signal. The resistance should ideally be close to zero ohms.
Shielded Wiring: Shielded wiring protects the sensor signal from interference. Damage to the shielding can lead to signal corruption.
Impact on Adaptive Cruise Control (ACC): A faulty sensor can affect ACC's ability to maintain lane position, as ACC relies on accurate steering input.
Impact on Lane Departure Warning (LDW): Similarly, a faulty sensor can impair the functionality of the LDW system.
Frequently Asked Questions:
What does the C0473 code mean? It indicates that the steering handwheel speed sensor is sending a voltage signal that is too high. This usually means a problem in the sensor circuit.
Can I still drive my car with the C0473 code? While you can drive, it's not recommended. The EPS and stability control systems may not function correctly, compromising safety.
How do I fix the C0473 code? Troubleshooting involves checking the wiring, sensor, and connectors for damage or corrosion. Repairs may involve replacing the sensor or fixing wiring issues.
Is the steering handwheel speed sensor the same as the steering angle sensor? No, they are different sensors, although they are often located near each other. The speed sensor measures the speed of the steering wheel's rotation, while the angle sensor measures the position or angle of the steering wheel.
Can a bad battery cause the C0473 code? While a low battery can sometimes cause erratic electrical behavior, it's less likely to be the direct cause of a C0473 code. It's best to diagnose the steering system directly.
Conclusion:
The C0473 code signifies a high voltage signal from the steering handwheel speed sensor, potentially impacting crucial vehicle systems like EPS and ESC. Thorough diagnosis and repair, involving wiring checks, sensor testing, and connector inspection, are essential to restore proper functionality and ensure safe vehicle operation.