Quick Answer
P0291 means: DTC P0291 means there's a problem with the turbocharger or supercharger boost pressure sensor circuit.
Can I drive with P0291? Immediate attention is recommended to avoid further engine damage.
Common Questions
What does P0291 mean and how does it affect my car?
DTC P0291 signifies that the turbocharger or supercharger boost pressure sensor isn't functioning as expected. This could lead to reduced engine performance, decreased fuel efficiency, and potential long-term engine damage if not addressed.
What are the most common causes of P0291 and how much does it cost to fix?
The most common causes include a faulty boost pressure sensor, turbocharger issues, and boost leaks. Repair costs can range from $150 for a sensor replacement to over $3,000 for a turbocharger replacement.
Can I drive my car with P0291 or should I stop immediately?
It's advisable to avoid driving your vehicle if you see the P0291 code, as it could lead to further engine damage. Immediate diagnostic attention is recommended.
How can I diagnose P0291 myself using GeekOBD APP?
Using the GeekOBD APP, you can perform an OBD2 scan to retrieve codes and view freeze frame data. This helps you understand the conditions under which the P0291 code was triggered.
What vehicles are most commonly affected by P0291?
P0291 is frequently seen in 2015-2020 Ford Focus and 2016-2019 Chevrolet Cruze models, among others. Always check for specific recalls or TSBs for your vehicle.
How can I prevent P0291 from happening again?
Regular maintenance, including inspections of the turbocharger and boost system, can help prevent P0291. Ensure all connections are secure and replace any worn hoses promptly.
What is P0291?
The DTC P0291 indicates that the engine control module (ECM) has detected a malfunction in the turbocharger or supercharger boost pressure sensor circuit. In simpler terms, it means that the system isn't generating the expected boost pressure that helps your engine perform efficiently. For vehicles equipped with a turbocharger, this code often relates to issues such as a faulty boost pressure sensor, a malfunctioning turbocharger, or even a boost leak in the intake system. If your vehicle experiences this code, you might notice a significant decrease in engine performance, reduced acceleration, and lower fuel efficiency. The problem can escalate if not addressed, potentially leading to more severe engine damage over time, including turbo failure or excessive engine wear. It's crucial to act promptly and have a thorough diagnostic performed to identify the specific issue causing this code to appear. If you own a turbocharged vehicle, understanding DTC P0291 can save you from costly repairs and help maintain the optimal performance of your engine.
System: P - Powertrain (Engine, Transmission, Emissions)
Symptoms
Common symptoms when P0291 is present:
- Check engine light illuminates and remains on, indicating a persistent issue with the boost system.
- Engine hesitates during acceleration, making it difficult to reach desired speeds or maintain power.
- Fuel economy decreased by 10-15%, significantly affecting your wallet at the pump.
- Unusual turbo noises, such as whistling or grinding, may indicate mechanical failure.
- Loss of power during highway speeds, causing safety concerns if merging or overtaking.
Possible Causes
Most common causes of P0291 (ordered by frequency):
- Faulty boost pressure sensor - This is the most common cause, accounting for about 40% of P0291 cases. The sensor may not be providing accurate readings to the ECM.
- Turbocharger malfunction - A failing turbo can lead to insufficient boost, often due to internal wear or failure of components like the wastegate.
- Boost leaks in the intake system - Cracks or loose connections in the intake hoses can cause a significant drop in boost pressure, making this a frequent issue.
- Electrical issues - Damaged wiring or poor connections in the sensor circuit can lead to incorrect readings and trigger the P0291 code.
- Rarely, software glitches in the ECM - In some cases, the vehicle's computer may require a software update to resolve false readings.
P0291 Repair Costs
Cost Breakdown by Repair Type
Boost Pressure Sensor Replacement
Replacing the faulty boost pressure sensor that failed to provide accurate readings.
- Total: $150 - $300
- Success rate: 95%
Turbocharger Repair or Replacement
Repairing or replacing the turbocharger if it's found to be malfunctioning.
- Total: $1,000 - $3,000
- Success rate: 90%
Intake System Repair
Fixing boost leaks in the intake system by replacing hoses or seals.
- Total: $100 - $500
- Success rate: 85%
Money-Saving Tips for P0291
- 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 P0291 Diagnosis Process
Follow these systematic steps to accurately diagnose P0291. 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 (5-10 minutes)
Step 1: Initial visual inspection - Check for obvious signs like damaged wiring, loose connections, or corrosion (5-10 minutes).
Step 2: Step 2: OBD2 scan with GeekOBD APP - Retrieve all codes and freeze frame data to understand the fault context (10-15 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: Step 3: Component testing - Use a multimeter to test the boost pressure sensor for proper voltage and resistance (20-30 minutes)
Step 3: Component testing - Use a multimeter to test the boost pressure sensor for proper voltage and resistance (20-30 minutes).
Step 4: Step 4: System function test - Verify the turbocharger operation and check for boost pressure with a gauge (10-15 minutes)
Step 4: System function test - Verify the turbocharger operation and check for boost pressure with a gauge (10-15 minutes).
Step 5: Step 5: Road test verification - Drive the vehicle under various conditions to confirm repair success and ensure no codes reappear (15-20 minutes)
Step 5: Road test verification - Drive the vehicle under various conditions to confirm repair success and ensure no codes reappear (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: Turbocharger Replacement on 2017 Ford Focus
Vehicle: 2017 Ford Focus, 45,000 miles
Problem: Customer reported loss of power and illuminated check engine light.
Diagnosis: Diagnostic scan revealed DTC P0291. Visual inspection showed a worn turbocharger.
Solution: Replaced the turbocharger assembly with a new unit.
Cost: $2,500 (parts: $1,800; labor: $700)
Result: Vehicle performance restored; no codes reappeared after follow-up.
Case Study 2: Boost Pressure Sensor Fix on 2018 Chevrolet Cruze
Vehicle: 2018 Chevrolet Cruze, 32,000 miles
Problem: Check engine light was on, and engine was sluggish.
Diagnosis: DTC P0291 was confirmed; sensor testing indicated failure.
Solution: Replaced the boost pressure sensor and cleared the codes.
Cost: $200 (parts: $100; labor: $100)
Result: Engine performance improved; customer satisfied with quick resolution.