Turbo/Supercharger Boost Sensor B Circuit (Bank 2)
The P0240 code means the vehicle's onboard diagnostic system has detected: Turbo/Supercharger Boost Sensor B Circuit (Bank 2). This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- moderate
- Estimated cost
- $80 - $400 (parts and labor)
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Common Symptoms
- Check Engine Light on
- Bank 2 turbo boost reduced
- Power loss from Bank 2 cylinders
- Possible limp mode on twin-turbo systems
Probable Causes (Ranked by Likelihood)
- Faulty Bank 2 turbo boost sensor Very High
- Wiring damage to Bank 2 boost sensor High
- Boost leak on Bank 2 intake tract Moderate
- PCM circuit fault for Bank 2 Low
Frequently Asked Questions
What is the Bank 2 boost sensor?
On twin-turbo engines, each turbocharger has its own boost sensor. The Bank 2 sensor monitors boost pressure from the turbo serving Bank 2 cylinders.
Can I drive a twin-turbo with P0240?
You can drive short distances, but the PCM may limit Bank 2 boost, resulting in uneven power delivery and reduced overall performance.
Is P0240 different from P0236?
P0236 refers to boost sensor B in general. P0240 specifically indicates the boost sensor circuit for the Bank 2 turbocharger on twin-turbo engines.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
-
Read Bank 2 boost sensor PID on scan tool. Compare to Bank 1 at idle (should be equal at atmospheric).
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Inspect Bank 2 boost sensor connector and wiring for damage.
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Pressure-test Bank 2 intake tract for boost leaks.
-
Measure sensor output voltage and compare to Bank 1 sensor.
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
Commonly Affected Vehicles
- 2010-2020 Ford F-150 (3.5L EcoBoost)
- 2012-2019 BMW 535i (3.0T twin-turbo)
- 2008-2018 Audi S4 (3.0T)
- 2011-2020 Mercedes-Benz E400 (3.0T)
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