P0391 Code - Camshaft Position Sensor 'B' Circuit Range/Performance Bank 2
Quick Answer
The diagnostic trouble code P0391 indicates a problem with the Camshaft Position Sensor 'B' Circuit Range/Performance in Bank 2. Common causes include Faulty Camshaft Position Sensor: The sensor itself may be malfunctioning, providing incorrect readings to the ECM, Wiring Issues: Damaged or corroded wiring connecting the sensor to the ECM can disrupt the signal transmission, Timing Chain/Belt Problems: Issues with the timing chain or belt can affect the camshaft's position, triggering this code. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P0391 indicates Camshaft Position Sensor 'B' Circuit Range/Performance Bank 2.
- Common causes
- Common causes include Faulty Camshaft Position Sensor: The sensor itself may be malfunctioning, providing incorrect readings to the ECM, Wiring Issues: Damaged or corroded wiring connecting the sensor to the ECM can disrupt the signal transmission, Timing Chain/Belt Problems: Issues with the timing chain or belt can affect the camshaft's position, triggering this code.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code P0391 Description
The diagnostic trouble code P0391 indicates a problem with the Camshaft Position Sensor 'B' Circuit Range/Performance in Bank 2. The camshaft position sensor is responsible for monitoring the position of the camshaft in relation to the crankshaft. This information is crucial for the engine control module (ECM) to determine the optimal timing for fuel injection and ignition. In Bank 2, the sensor is located on the side of the engine where the number 2 cylinder is located.
Common Causes of P0391
- Faulty Camshaft Position Sensor: The sensor itself may be malfunctioning, providing incorrect readings to the ECM.
- Wiring Issues: Damaged or corroded wiring connecting the sensor to the ECM can disrupt the signal transmission.
- Timing Chain/Belt Problems: Issues with the timing chain or belt can affect the camshaft's position, triggering this code.
- ECM Malfunction: A malfunctioning ECM can also lead to incorrect camshaft position readings and trigger this code.
- Mechanical Engine Issues: Problems with the engine components, such as the camshaft itself, can also contribute to this code being triggered.
Symptoms of P0391
- Check Engine Light: The most common symptom associated with this code is the illumination of the check engine light on the dashboard.
- Rough Idling: The engine may idle roughly or inconsistently due to incorrect camshaft position readings.
- Decreased Fuel Efficiency: A faulty camshaft position sensor can lead to improper fuel delivery, resulting in decreased fuel efficiency.
- Engine Misfires: Incorrect camshaft position readings can cause misfires, leading to a noticeable decrease in engine performance.
- Engine Stalling: In severe cases, the engine may stall unexpectedly due to the incorrect timing caused by the faulty camshaft position sensor.
How to Fix P0391
- Diagnose the Issue: Use a diagnostic scanner to retrieve the trouble code and perform further testing to pinpoint the exact cause of the problem.
- Replace Camshaft Position Sensor: If the sensor is found to be faulty, replace it with a new one following the manufacturer's guidelines.
- Check Wiring: Inspect the wiring harness for any damage or corrosion and repair or replace as necessary.
- Verify Timing Chain/Belt: Ensure that the timing chain or belt is properly aligned and functioning correctly to avoid future issues.
- Clear Codes and Test Drive: Clear the trouble codes from the ECM, and test drive the vehicle to ensure that the issue has been resolved.
Cost to Fix P0391
The typical repair costs for addressing the Camshaft Position Sensor 'B' Circuit Range/Performance Bank 2 code can range from $100 to $300, including parts and labor. However, it's important to note that specific diagnosis time and labor rates at auto repair shops can vary based on factors such as location, vehicle make and model, and engine type. Auto repair shops commonly charge between $80 and $150 per hour for labor, but rates may be higher in metropolitan areas or at dealerships, while independent shops may charge less. It's recommended to check local rates for a more accurate estimate before proceeding with the repair.
Tech Notes for P0391
When is the Code Detected?
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Code P0391 Information for Specific Makes
- P0391 Audi — Camshaft Position Sensor 'B' Circuit Range/Performance Bank 2
- P0391 Hyundai — Camshaft Position Sensor 'B' Circuit Range/Performance Bank 2
- P0391 KIA — Camshaft Position Sensor 'B' Circuit Range/Performance Bank 2
- P0391 Volkswagen — Camshaft Position Sensor 'B' Circuit Range/Performance Bank 2
Frequently Asked Questions about P0391 Code
1. What are the common symptoms of OBDII code P0391 (Camshaft Position Sensor 'B' Circuit Range/Performance Bank 2)?
- Common symptoms include engine misfires, rough idling, poor acceleration, and potentially stalling while driving.
2. What are the possible causes of OBDII code P0391?
- The code P0391 can be triggered by a faulty camshaft position sensor, wiring issues in the sensor circuit, or problems with the engine control module (ECM).
3. How can I diagnose the cause of OBDII code P0391?
- Diagnosing the code typically involves checking the camshaft position sensor for proper operation, inspecting the sensor wiring for damage, and testing the ECM for any faults.
4. Can a dirty camshaft position sensor cause code P0391?
- Yes, a dirty or contaminated camshaft position sensor can lead to erratic readings and trigger code P0391. Cleaning or replacing the sensor may resolve the issue.
5. Is it safe to drive with OBDII code P0391 active?
- It is not recommended to drive with code P0391 active, as it can lead to engine performance issues and potential breakdowns. It's best to address the problem promptly.
6. How can I repair OBDII code P0391?
- Repairing code P0391 may involve replacing the camshaft position sensor, repairing any damaged wiring, or reprogramming the ECM to resolve the circuit range/performance issue.
7. Can a DIY enthusiast fix OBDII code P0391 at home?
- Depending on your experience and tools, some DIY enthusiasts may be able to diagnose and repair code P0391 at home. However, professional assistance may be needed for complex issues.
8. Will resetting the OBDII code P0391 clear the problem?
- Resetting the code may temporarily clear the check engine light, but if the underlying issue causing code P0391 is not addressed, the problem is likely to reoccur.
9. How long does it typically take to repair OBDII code P0391?
- The repair time for code P0391 can vary depending on the cause and complexity of the issue. It may take anywhere from 1 to 4 hours to diagnose and fix the problem.
10. Can OBDII code P0391 affect fuel efficiency?
- Yes, code P0391 can impact fuel efficiency due to engine performance issues. Resolving the code promptly can help improve fuel economy.
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