Quick Answer
U0420 means: The U0420 code signifies that your vehicle's ECU is receiving invalid data from the steering angle sensor.
Can I drive with U0420? Address this issue immediately to maintain vehicle safety and functionality.
Common Questions
What does U0420 mean and how does it affect my car?
The U0420 code indicates an issue with the data received from the steering angle sensor, affecting your car's steering response and safety features. This can lead to unpredictable handling and potential safety hazards if not addressed promptly.
What are the most common causes of U0420 and how much does it cost to fix?
Common causes include a faulty steering angle sensor (around $150-$300) and damaged wiring (about $100-$200). Repair costs can vary based on the specific issue and labor rates in your area.
Can I drive my car with U0420 or should I stop immediately?
It's advisable to stop driving your vehicle if you see the U0420 code, as it can lead to unsafe driving conditions. Immediate inspection and repair are recommended to ensure safety.
How can I diagnose U0420 myself using GeekOBD APP?
You can use the GeekOBD APP to scan your vehicle for diagnostic trouble codes, view freeze frame data, and monitor live sensor readings. This will help you pinpoint the issue with the steering angle sensor.
What vehicles are most commonly affected by U0420?
Vehicles such as the 2015-2018 Chevrolet Equinox and GMC Terrain are frequently affected by the U0420 code. Always check for any recalls or technical service bulletins related to your specific model.
How can I prevent U0420 from happening again?
Regular maintenance, including inspections of the steering system and electrical connections, can help prevent the recurrence of U0420. Keeping the vehicle away from harsh environments can also reduce wear on components.
What is U0420?
The DTC U0420 relates to an issue with the communication between your vehicle's Electronic Control Unit (ECU) and the steering angle sensor. This code indicates that the data received from the steering angle sensor is invalid or not within the expected range. The steering angle sensor is crucial for various vehicle systems, including stability control and anti-lock braking systems. When this sensor fails or communicates incorrectly, it can lead to issues such as loss of traction control, unexpected behavior during maneuvers, and even safety risks in adverse driving conditions. In practical terms, this means if you're driving a vehicle like the 2015 Chevrolet Equinox and you see a check engine light along with this code, you may notice problems with steering responsiveness or stability, leading to a less safe driving experience. Ignoring this issue can lead to more serious problems down the line, including complete failure of stability controls. Therefore, it’s essential to address this code promptly to ensure your vehicle operates safely and efficiently.
System: U - Network (Communication, CAN Bus)
Symptoms
Common symptoms when U0420 is present:
- Check engine light stays on constantly, indicating a persistent issue that needs attention.
- Steering feels unresponsive or laggy, making it difficult to maneuver the car effectively.
- Traction control warning light may illuminate, affecting the vehicle's ability to handle slippery surfaces safely.
- Unusual steering noises could occur when turning, indicating a potential mechanical issue.
- Increased fuel consumption might be observed due to the vehicle's stability and traction systems functioning improperly.
Possible Causes
Most common causes of U0420 (ordered by frequency):
- The most common cause is a faulty steering angle sensor, with a likelihood of about 60%. This sensor may fail due to wear and tear or electrical issues.
- A second cause could be damaged wiring or connectors related to the steering sensor, which can disrupt communication. This typically occurs in vehicles with high mileage.
- A third cause might be software glitches in the ECU or compatibility issues after updates, which can be prevented by regular maintenance and software checks.
- Less commonly, issues within the ECU itself can cause miscommunication with the steering angle sensor. This issue is serious as it could lead to total system failure.
- Rarely, external factors like water intrusion or corrosion can affect the sensor's performance, particularly in vehicles frequently exposed to harsh conditions.
U0420 Repair Costs
Cost Breakdown by Repair Type
Steering Angle Sensor Replacement
Replacing the faulty steering angle sensor to ensure accurate data transmission.
- Total: $150 - $300
- Success rate: 85%
Wiring Repair
Repairing damaged wiring or connectors that may be causing signal interference.
- Total: $100 - $200
- Success rate: 75%
Money-Saving Tips for U0420
- Start with the most common and least expensive repairs first
- Use GeekOBD APP to confirm diagnosis before replacing expensive parts
- Consider preventive maintenance to avoid future occurrences
- Compare prices for OEM vs aftermarket parts based on your needs
- Address the issue promptly to prevent more expensive secondary damage
Diagnostic Steps
Professional U0420 Diagnosis Process
Follow these systematic steps to accurately diagnose U0420. Each step builds on the previous one to ensure accurate diagnosis.
Step 1: Initial visual inspection - Check for obvious signs like damaged wiring, loose connections, or corrosion (5-10 minutes)
Step 2: OBD2 scan with GeekOBD APP - Retrieve all codes and freeze frame data to understand the fault context (10-15 minutes)
Step 3: Component testing - Use a multimeter or specific diagnostic tools to test the steering angle sensor and associated circuits (20-30 minutes)
Step 4: System function test - Verify proper operation after repairs and clear codes to ensure the issue is resolved (10-15 minutes)
Step 5: Road test verification - Drive the vehicle under various conditions to confirm repair success and monitor the behavior of the steering system (15-20 minutes)
Important Notes
- Always verify the repair with GeekOBD APP after completing diagnostic steps
- Clear codes and test drive to ensure the problem is resolved
- Address underlying causes to prevent code recurrence
Real Repair Case Studies
Case Study 1: Steering Angle Sensor Replacement on 2016 Chevrolet Equinox
Vehicle: 2016 Chevrolet Equinox, 65,000 miles
Problem: Customer reported persistent check engine light and unresponsive steering.
Diagnosis: Initial OBD2 scan revealed U0420 code. Visual inspection showed a damaged steering angle sensor.
Solution: Replaced the steering angle sensor and recalibrated the system.
Cost: $250 (sensor: $150, labor: $100)
Result: Post-repair, the check engine light was cleared, and steering responsiveness was restored.
Case Study 2: Wiring Repair on 2017 GMC Terrain
Vehicle: 2017 GMC Terrain, 50,000 miles
Problem: Customer experienced traction control warning light and steering issues.
Diagnosis: OBD2 scan confirmed U0420. Wiring inspection revealed frayed wires near the sensor.
Solution: Repaired damaged wiring and secured connections.
Cost: $150 (labor: $100, wiring parts: $50)
Result: Traction control light turned off, and steering performance returned to normal.