P0240
Turbocharger/Supercharger Boost Sensor B Circuit Range/Performance
Turbo/boost control
Generic OBD-II
High
What it means
P0240 means boost pressure sensor "B" is reporting a value that's out of its expected range or doesn't track the engine's actual boost. The ECM relies on this sensor to manage the turbo, so an implausible reading usually triggers reduced power to stay safe. The fault is normally in the sensor, its wiring, or a boost leak rather than the turbo itself.
High
Can I keep driving? Usually yes, but the engine may limit power to protect the turbo — expect softer acceleration until it's fixed.
Common symptoms
What you'll notice
- Check-engine light on
- Reduced power or limp mode
- Weak or erratic boost under acceleration
- Poor fuel economy
Common causes
Most likely first
- Faulty boost pressure sensor B reading out of rangeLikely
- Wiring damage or a poor connection in the sensor circuitCommon
- Loose or corroded connector at the sensorCommon
- Intake/boost leak skewing the sensor's readingLess often
- Failed engine control module (least likely)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and compare the sensor B live value to actual boost pressure.
- Inspect the sensor connector and wiring for corrosion, chafing, or loose pins.
- Check for boost/intake leaks that could make the reading implausible.
- Confirm reference voltage and ground, then test the sensor output; replace the sensor if out of range. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0240?+
Short-term yes, though the engine may reduce boost and power. It won't prevent the car from starting — have the sensor circuit checked soon.
Can I just clear P0240?+
It returns until the sensor, wiring, or a boost leak is corrected. Fix the cause first, then clear it.
Related codes
Often seen with P0240
Read & clear P0240 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX