Quick Answer
C0191 means: C0191 indicates a problem with the Vehicle Speed Sensor or ABS system.
Can I drive with C0191? Immediate investigation is recommended to prevent safety issues.
Common Questions
What does C0191 mean and how does it affect my car?
C0191 indicates a problem with the Vehicle Speed Sensor or the Anti-lock Brake System (ABS). This can lead to compromised braking performance, which is critical for your safety. You may notice warning lights on your dashboard and unusual braking behavior, which can affect your control over the vehicle.
What are the most common causes of C0191 and how much does it cost to fix?
The most common cause of C0191 is a faulty Vehicle Speed Sensor, with repairs typically costing between $150 and $300. Other causes, such as damaged wiring or a failing ABS module, can increase costs significantly, potentially reaching $1,200.
Can I drive my car with C0191 or should I stop immediately?
It's advisable to avoid driving your vehicle until the issue is resolved. Ignoring the C0191 code can lead to brake failure during critical moments, posing a serious safety risk.
How can I diagnose C0191 myself using GeekOBD APP?
You can use the GeekOBD APP to scan for DTC codes, view freeze frame data, and check for any related issues that could help pinpoint the problem. Look for any anomalies in the vehicle's speed readings and check for additional trouble codes that may provide more context.
What vehicles are most commonly affected by C0191?
DTC C0191 is commonly found in 2007-2013 Chevrolet Silverado and GMC Sierra models, but it can also affect other vehicles equipped with similar ABS and speed sensor configurations.
How can I prevent C0191 from happening again?
Regularly inspect your vehicle's brake system and wiring harnesses for wear and tear. Ensure that all electrical connections are secure and free from corrosion. Additionally, keeping up with routine maintenance can help catch potential issues early.
What is C0191?
The diagnostic trouble code C0191 pertains to the Vehicle Speed Sensor (VSS) or the Anti-lock Brake System (ABS) in vehicles like the 2007-2013 Chevrolet Silverado and GMC Sierra. This code is triggered when the ABS module detects an issue with the signal from the speed sensor, which is crucial for monitoring the vehicle's speed and ensuring optimal brake performance. When this code appears, it often leads to the ABS light illuminating on the dashboard, indicating that the anti-lock braking system may not function correctly. This can compromise vehicle safety, especially during emergency braking situations. This fault can affect other systems like traction control, leading to further complications if not addressed promptly. Common issues associated with C0191 include erratic braking performance, increased stopping distances, and a general feeling of instability when braking. If left unresolved, the long-term implications could include increased wear on brake components and even the potential for accidents due to compromised braking ability. Car owners experiencing this code should take immediate action to diagnose and rectify the issue.
System: C - Chassis (ABS, Steering, Suspension)
Symptoms
Common symptoms when C0191 is present:
- ABS warning light is illuminated on the dashboard, indicating a fault in the brake system.
- Vehicle may experience erratic braking behavior, such as the brakes feeling 'soft' or 'hard' unexpectedly.
- Traction control may become disabled, leading to reduced vehicle stability in slippery conditions.
- Unusual noises from the brake system, such as grinding or squeaking, when applying brakes.
- Increased stopping distance due to compromised braking performance.
Possible Causes
Most common causes of C0191 (ordered by frequency):
- Faulty Vehicle Speed Sensor (VSS) is the most common cause, accounting for about 60% of cases. A defective sensor may not send accurate speed data to the ABS module.
- Damaged wiring or connectors associated with the VSS can cause signal loss or interference, making up about 25% of reports.
- Worn brake components such as pads or rotors can lead to an inaccurate reading from the ABS, potentially contributing to the C0191 code.
- Less common but serious causes include failure of the ABS module itself, which can render the anti-lock braking system inoperable.
- Rarely, software issues within the vehicle's computer systems can trigger this code, necessitating a software update or reprogramming.
C0191 Repair Costs
Cost Breakdown by Repair Type
Vehicle Speed Sensor Replacement
Replacing a faulty Vehicle Speed Sensor often resolves the C0191 code.
- Total: $150 - $300
- Success rate: 85%
ABS Module Repair
Repairing or replacing the ABS module if it's found to be faulty.
- Total: $500 - $1,200
- Success rate: 75%
Money-Saving Tips for C0191
- 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 C0191 Diagnosis Process
Follow these systematic steps to accurately diagnose C0191. Each step builds on the previous one to ensure accurate diagnosis.
Step 1: Step 1: Initial visual inspection - Check for obvious signs like damaged wiring, loose connections, or corrosion around the speed sensor and ABS module (5-10 minutes)
Step 1: Initial visual inspection - Check for obvious signs like damaged wiring, loose connections, or corrosion around the speed sensor and ABS module (5-10 minutes).
Step 2: Step 2: OBD2 scan with GeekOBD APP - Use the app to retrieve all codes and freeze frame data, helping you understand the fault context (10-15 minutes)
Step 2: OBD2 scan with GeekOBD APP - Use the app to retrieve all codes and freeze frame data, helping you understand the fault context (10-15 minutes).
Step 3: Step 3: Component testing - Employ a multimeter to test the VSS and its wiring for proper voltage and continuity (20-30 minutes)
Step 3: Component testing - Employ a multimeter to test the VSS and its wiring for proper voltage and continuity (20-30 minutes).
Step 4: Step 4: System function test - After repairs, verify proper operation of the ABS and clear codes to reset the system (10-15 minutes)
Step 4: System function test - After repairs, verify proper operation of the ABS and clear codes to reset the system (10-15 minutes).
Step 5: Step 5: Road test verification - Drive the vehicle under various conditions to confirm repair success and proper ABS functionality (15-20 minutes)
Step 5: Road test verification - Drive the vehicle under various conditions to confirm repair success and proper ABS functionality (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: Failed Vehicle Speed Sensor in 2010 Chevrolet Silverado
Vehicle: 2010 Chevrolet Silverado, 85,000 miles
Problem: Customer reported ABS light on and inconsistent braking performance.
Diagnosis: After scanning with GeekOBD, C0191 was confirmed. A visual inspection revealed a damaged Vehicle Speed Sensor.
Solution: Replaced the Vehicle Speed Sensor and cleared the trouble code.
Cost: $220 (sensor and labor)
Result: Post-repair, ABS light was off, and braking performance was restored.
Case Study 2: ABS Module Failure in 2012 GMC Sierra
Vehicle: 2012 GMC Sierra, 70,000 miles
Problem: Customer complained of ABS light on and unstable braking.
Diagnosis: Diagnostic testing revealed C0191, and further testing indicated a faulty ABS module.
Solution: Replaced the ABS module and reprogrammed the system.
Cost: $950 (parts and labor)
Result: Vehicle braking was normalized, and all warning lights cleared.