C0391 - Understanding the Steering Angle Sensor Malfunction in 2010-2015 Chevrolet Equinox, GMC Terrain, and More

Quick Answer

C0391 means: C0391 indicates a problem with the steering angle sensor, affecting stability control systems.

Fix: Check and replace faulty components Cost: $150 - $400 Time: 90-180 minutes

Can I drive with C0391? Immediate attention is recommended to ensure safety and vehicle handling.

Common Questions

What does C0391 mean and how does it affect my car?

C0391 indicates a malfunction in the steering angle sensor, which is essential for the vehicle's stability control. If this code appears, it may compromise your vehicle's handling and safety features. It's crucial to address it immediately to ensure safe driving.

What are the most common causes of C0391 and how much does it cost to fix?

The primary cause of C0391 is a faulty steering angle sensor, with repair costs typically ranging from $150 to $400 for replacement. Other causes include damaged wiring or calibration issues, which can also incur additional costs depending on the extent of the damage.

Can I drive my car with C0391 or should I stop immediately?

Driving with C0391 can be risky, as it may disable crucial safety systems like traction control. It's advisable to stop driving and address the issue as soon as possible to avoid potential accidents.

How can I diagnose C0391 myself using GeekOBD APP?

You can use the GeekOBD APP to retrieve the diagnostic trouble codes from your vehicle. Simply connect the app to your OBD2 port, run a scan, and check for any associated codes with C0391, which can help guide your next steps.

What vehicles are most commonly affected by C0391?

C0391 is commonly found in vehicles like the 2010-2015 Chevrolet Equinox and GMC Terrain. These vehicles often experience this issue due to the design of their steering systems.

How can I prevent C0391 from happening again?

Regular maintenance, including checking the steering system and wiring for wear and tear, can help prevent C0391. Ensure that any repairs involving the steering system are properly calibrated, and consider using quality parts to reduce the chance of recurrence.

What is C0391?

DTC C0391 indicates a malfunction related to the steering angle sensor, which is crucial for a vehicle's stability control and traction control systems. This code typically appears when the sensor's output is inconsistent or if there is a failure in the circuit. The steering angle sensor provides data about the position of the steering wheel to the vehicle’s electronic control unit (ECU). When this data is faulty, it can lead to compromised safety features such as Electronic Stability Control (ESC) and Anti-lock Braking System (ABS). If you own a vehicle like the 2010-2015 Chevrolet Equinox or GMC Terrain, experiencing this code could result in warning lights on your dashboard, particularly the ESC or ABS warning. Ignoring this code can lead to reduced vehicle handling and stability, especially in adverse weather conditions, increasing the risk of accidents. It's essential to address DTC C0391 promptly to ensure your vehicle's safety systems function correctly. If you're experiencing signs of trouble, seek a professional diagnostic to avoid further complications.

System: C - Chassis (ABS, Steering, Suspension)

Symptoms

Common symptoms when C0391 is present:

  • The check engine light remains illuminated, indicating a fault in the steering system.
  • The steering feels unresponsive or excessively loose, making it difficult to control the vehicle.
  • The vehicle's traction control and stability control systems may become disabled, leading to potential safety hazards.
  • You may notice a fluctuating speedometer or erratic vehicle behavior during turns.
  • Unusual noises from the steering column when turning the wheel could indicate sensor issues.

Possible Causes

Most common causes of C0391 (ordered by frequency):

  1. The most common cause is a faulty steering angle sensor, with a likelihood of about 60%. This could be due to wear and tear over time or an electrical failure within the sensor.
  2. Another common cause is damaged wiring or poor connections in the sensor circuit, which can affect signal transmission and is likely around 25%. Regular inspections can help prevent this.
  3. Thirdly, calibration issues following a previous repair can lead to C0391. Ensuring that the sensor is correctly calibrated after any related repair is crucial for preventing this code.
  4. Less common but serious causes include a malfunctioning electronic control unit (ECU) that may need replacement, which can be quite costly.
  5. A rare cause could be internal mechanical failure in the steering column, which, while not common, can lead to significant repairs if not addressed quickly.

C0391 Repair Costs

Cost Breakdown by Repair Type

Steering Angle Sensor Replacement

Replacing the steering angle sensor to restore proper function.

  • Total: $150 - $400
  • Success rate: 90%
Wiring Repair

Repairing damaged wiring or connectors in the sensor circuit.

  • Total: $100 - $250
  • Success rate: 85%
Money-Saving Tips for C0391
  • 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 C0391 Diagnosis Process

Follow these systematic steps to accurately diagnose C0391. Each step builds on the previous one to ensure accurate diagnosis.

Step 1: Step 1: Perform an initial visual inspection of the steering column and related wiring for obvious signs like damaged wires or loose connections (5-10 minutes)

Step 1: Perform an initial visual inspection of the steering column and related wiring for obvious signs like damaged wires or loose connections (5-10 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 2: Step 2: Use the GeekOBD APP to run an OBD2 scan, retrieving all relevant codes and freeze frame data to contextualize the fault (10-15 minutes)

Step 2: Use the GeekOBD APP to run an OBD2 scan, retrieving all relevant codes and freeze frame data to contextualize the fault (10-15 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 3: Step 3: Conduct component testing using a multimeter or specialized tools to measure the sensor’s output and resistance (20-30 minutes)

Step 3: Conduct component testing using a multimeter or specialized tools to measure the sensor’s output and resistance (20-30 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 4: Step 4: After potential repairs, perform a system function test to verify the sensor's operation and clear any codes (10-15 minutes)

Step 4: After potential repairs, perform a system function test to verify the sensor's operation and clear any codes (10-15 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 5: Step 5: Carry out a road test to ensure the vehicle operates correctly under various conditions and that the C0391 code does not return (15-20 minutes)

Step 5: Carry out a road test to ensure the vehicle operates correctly under various conditions and that the C0391 code does not return (15-20 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.

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 in a 2012 Chevrolet Equinox

Vehicle: 2012 Chevrolet Equinox, 85,000 miles

Problem: Customer reported a persistent check engine light and unresponsive steering.

Diagnosis: A diagnostic scan revealed DTC C0391, indicating a faulty steering angle sensor. Further inspection confirmed the sensor was not sending accurate data.

Solution: The steering angle sensor was replaced with a new OEM part, and the system was recalibrated.

Cost: $350 (including parts and labor)

Result: The steering responsiveness improved, and the check engine light was cleared successfully.

Case Study 2: Wiring Repair on a 2013 GMC Terrain

Vehicle: 2013 GMC Terrain, 70,000 miles

Problem: Customer noticed traction control warning light and erratic steering behavior.

Diagnosis: DTC C0391 was retrieved, and inspection revealed damaged wiring in the sensor circuit.

Solution: The damaged wiring was repaired, and the sensor was tested for proper function.

Cost: $200 (including parts and labor)

Result: After repairs, the warning lights were cleared, and the vehicle handled normally.

Diagnose C0391

Use GeekOBD APP for professional diagnosis!

  • Real-time data monitoring
  • Advanced diagnostic features
  • Step-by-step repair guidance
  • Professional-grade analysis
Download GeekOBD APP Get MOBD Adapter

Code Information

Code: C0391
System: Chassis (ABS, Steering, Suspension)
Severity: HIGH
Category: Chassis Codes