P0239: Turbocharger/Supercharger Boost Sensor B Circuit
What to do
Expect reduced power. Worth establishing which turbocharger or which point in the charge path this sensor monitors before diagnosis begins.
What this code means
A circuit fault in the second boost pressure sensor. A second sensor appears on twin-turbo installations, where each turbocharger is measured separately, and on systems that measure pressure both before and after the intercooler so the module can detect a blocked cooler by the pressure drop across it.
Likely causes
Start here
- Faulty boost pressure sensor · moderate
- Corroded or loose connector · easy
- Open circuit in sensor wiring · moderate
Less common
- Boost leak in charge pipework · moderate
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
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