P0240
Fix within a few daysYour engine's computer is getting an unexpected signal from the secondary boost pressure sensor, indicating a problem with its circuit or performance.
Code P0240 means your boost sensor "B" circuit has a range or performance problem. Common causes: Faulty boost sensor (70%), wiring issues (20%). Drivability: Yes, but with reduced power. Repair cost: $50-$150 DIY, $150-$400 professional.
Can I Drive With P0240?
Yes, for short trips only
Essential trips under 10 miles, avoid highways and heavy acceleration. Fix within a few days.
Stop driving immediately if: Flashing CEL, significant power loss, loud engine noises, or a strong burning smell.
Symptoms of P0240
- 1Check Engine Light is on
- 2Reduced engine power or acceleration
- 3Engine feels sluggish or hesitant
- 4Poor fuel economy
- 5Engine may run rough at times
Common Causes of P0240
Parts most likely causing this code, ranked by probability
The sensor itself is faulty, sending incorrect or erratic voltage signals to the engine computer.
70% of P0240 cases are fixed by replacing this part
Damaged, corroded, or loose wiring and connectors can disrupt the sensor's signal to the engine computer.
20% of P0240 cases are fixed by repairing wiring or connectors
A significant leak in the turbo/supercharger system can cause the sensor to read pressures outside its expected range, triggering the code.
8% of P0240 cases are fixed by repairing boost/vacuum leaks
A rare but possible cause where the engine computer itself is unable to correctly process the sensor's input.
2% of P0240 cases are fixed by replacing the ECM/PCM
Check These First (Before Buying Parts)
- Visually inspect the boost pressure sensor 'B' and its electrical connector for any obvious damage, corrosion, or loose connections.
- Check the wiring harness leading to the sensor for any signs of chafing or cuts.
How to Diagnose P0240
- 1Visually inspect the boost pressure sensor 'B' and its electrical connector for any damage, corrosion, or loose connections.
- 2Check the wiring harness leading to the sensor for any signs of chafing, cuts, or breaks.
- 3Use a scan tool to monitor the boost pressure sensor 'B' readings (MAP/TIP sensor data) with the engine off (should read atmospheric pressure) and while driving under boost.
- 4Perform a boost leak test on the turbo/supercharger system to rule out any leaks.
- 5If readings are erratic or incorrect, test the sensor's voltage and ground circuits with a multimeter.
- 6If all other checks are good, replace the boost pressure sensor 'B'.
P0240 on Popular Vehicles
Ford F-150
2011-2024EcoBoost engines are prone to boost pressure sensor failures due to engine bay heat and vibrations. The sensor can give erratic readings before complete failure.
75% fixed by replacing the Boost Pressure Sensor 'B'
Chevrolet Silverado
2019-2024On turbocharged Silverado models, P0240 can point to a failing boost sensor or, less commonly, a compromised wiring harness near the sensor.
70% fixed by replacing the Boost Pressure Sensor 'B'
Honda Civic
2016-2024For 1.5T engines, P0240 can be caused by the boost sensor itself or, in some cases, a chafed wiring harness where it passes near engine components.
65% fixed by replacing the Boost Pressure Sensor 'B'
Frequently Asked Questions
What does P0240 mean?
P0240 indicates that your vehicle's engine computer has detected an issue with the signal from the secondary boost pressure sensor, meaning its readings are outside the expected range or performing erratically.
Can I drive with P0240?
Yes, you can drive with P0240, but expect reduced engine power and potentially worse fuel economy. You should fix this within a few days to prevent further issues.
Will P0240 clear itself?
No, P0240 will not clear itself. The engine computer stores this code until the underlying problem is fixed and the system passes its self-test, or until it is manually cleared with a scan tool.
How do I fix P0240 myself?
Start by inspecting the boost sensor 'B' wiring and connector for damage. If they look good, use a scan tool to monitor the sensor's live data. If the sensor readings are incorrect, replacing the boost pressure sensor 'B' is the next step.
How much does it cost to fix P0240?
A DIY fix for P0240 typically costs $50-$150 for the boost pressure sensor part. Professional repair at a shop will cost $150-$400, which includes diagnosis, the part, and labor.
P0240 keeps coming back - why?
If P0240 keeps returning, it means the root cause was not fully addressed. This often happens if you only replaced the sensor without checking for wiring damage, boost leaks, or if the new sensor is also faulty.
Will P0240 fail emissions/smog test?
Yes, P0240 will cause your vehicle to fail an emissions or smog test. The Check Engine Light being on is an automatic failure in most jurisdictions.
What's the difference between P0240 and P0236?
P0240 refers to a range/performance issue with the 'B' boost pressure sensor circuit, while P0236 refers to a similar range/performance issue with the 'A' boost pressure sensor circuit. They indicate a problem with different, though similar, sensors or their circuits.
P0240 on Ford F-150?
On Ford F-150s with EcoBoost engines, P0240 is often caused by a faulty MAP/TIP sensor (boost pressure sensor 'B') due to heat and vibrations. Inspecting the sensor and its connector is a common first step.
Questions to Ask Your Mechanic
Did you check the live data from the boost pressure sensor 'B' with a scan tool?
Good answer: Yes, the sensor was reading X psi at idle and Y psi under boost, which was inconsistent with expected values. We also checked the voltage signal.
Have you inspected the wiring and connector for the boost pressure sensor 'B' for any damage or corrosion?
Good answer: Absolutely, we visually inspected the harness and connector, and performed continuity and resistance checks to ensure the circuit is sound.
Repair Cost Estimate
DIY Repair
Parts only
$50-$150
Shop Repair
Parts + labor
$150-$400
Save $100-$250 by doing it yourself
Difficulty
intermediate
Time
0.5-2 hours
Intermediate - requires a scan tool for proper diagnosis and monitoring, in addition to basic hand tools.
Cost of Waiting
Ignoring P0240 can lead to continued reduced engine power and fuel economy. If the sensor provides incorrect data, your engine might run too rich or too lean under boost, which can cause long-term damage to components like spark plugs, oxygen sensors, and even the catalytic converter ($800-$2,500 repair).
While You're In There...
If the boost sensor is located near the air intake, it's a good time to check and replace the air filter if it's dirty, ensuring optimal airflow.
If the boost sensor requires removal of intake components for access, replacing the intake manifold gaskets prevents future vacuum or boost leaks and repeat labor.
Tools You'll Need
- Basic hand tools (sockets, wrenches)
- Multimeter
- OBD-II Scan Tool with live data capability
- Boost leak tester (optional, but recommended for thorough diagnosis)
P0240 is a common sensor-related code on turbocharged or supercharged vehicles. The repair is usually straightforward, and your engine will regain its full power and efficiency afterward.
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Your Next Steps
Step 1: Visually inspect the boost pressure sensor 'B' and its electrical connector and wiring for any damage, corrosion, or loose connections. Ensure the connector is fully seated.
Step 2: Use an OBD-II scan tool to monitor the live data for the boost pressure sensor 'B'. Compare its readings to atmospheric pressure with the engine off, and observe its behavior under acceleration. If readings are erratic or stuck, proceed to replacement.
Step 3: If visual inspection and scan tool data point to a faulty sensor, replace the boost pressure sensor 'B'. Clear the code and test drive the vehicle.