P0237

Universal

Turbocharger Boost Sensor A Circuit Low

Definition source: General OBD-II reference catalog
Definition verification: Not independently verified for display.
Time: Varies by diagnosis and vehicle | Diagnostic difficulty: Medium
Medium Severity

The engine controller has detected a voltage that is lower than expected in the circuit for turbocharger boost sensor A. This sensor reports boost pressure so the controller can manage engine operation. The code indicates a low circuit signal; it does not by itself prove that boost pressure is low or that the sensor needs replacement. Depending on the vehicle, the fault may cause reduced power or altered turbocharger control, though some vehicles may show no noticeable symptoms.

Report an error with this code

⚠️ Before You Begin (Safety First)

If the vehicle loses significant power, runs roughly, produces unusual smoke or noises, or shows signs of overheating, stop somewhere safe and arrange an inspection. If it drives normally, avoid hard acceleration and have the fault checked promptly.

Common Symptoms

  • The check-engine light may be on, with no obvious change in how the vehicle drives.
  • Reduced power or slower acceleration may occur if the engine controller limits output or changes turbocharger control in response to the unreliable signal.
  • Engine performance may feel inconsistent if the controller cannot use the boost sensor signal as intended.
  • Fuel economy may change if engine management is affected.

Common Causes

  • A damaged, loose or corroded connector may interfere with the boost sensor circuit.
  • Wiring damage, including a signal wire shorted to ground, may pull the circuit voltage low.
  • A problem with the sensor's reference-voltage or ground circuit may affect its output.
  • The boost sensor itself may have an internal electrical fault.
  • An engine controller or related circuit fault is possible and should be considered only after appropriate checks.

Diagnostic Steps

  1. Check whether the check-engine light is accompanied by reduced power, rough running, unusual smoke or noises. Stop driving if the vehicle seems unsafe or shows signs of overheating.
  2. With the engine off, visually inspect accessible wiring and the boost sensor connector for looseness, corrosion, damaged insulation or signs of rubbing. Do not pull on wires or disconnect components while the engine is running.
  3. If you have a compatible scan tool, record the code and any related codes before clearing anything. Related codes can help show whether the issue affects a shared circuit.
  4. Avoid replacing the sensor based only on this code. If the visual check does not reveal an obvious issue, have the sensor signal and its reference and ground circuits tested using vehicle-specific service information.

When to Call a Professional

Check the fault with a scan tool and review relevant sensor data. Inspect the sensor connector and wiring, then test the signal, reference and ground circuits using the vehicle-specific wiring diagram and service information. Confirm whether the signal problem is caused by the sensor, wiring, another circuit issue or the engine controller before replacing parts.

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Commonly Asked Questions

Does P0237 prove that the boost sensor is faulty?

No. It reports a low signal in the boost sensor A circuit. The cause could be the sensor, its wiring or connector, a reference or ground issue, or another circuit fault.

Does this code mean the turbo is producing too little boost?

Not by itself. The code describes a low electrical circuit signal, not a confirmed low-pressure condition. Further checks are needed to distinguish an electrical problem from a boost-pressure problem.

Can I keep driving with P0237?

It depends on how the vehicle behaves. If it drives normally, cautious driving to arrange diagnosis may be reasonable. Stop safely and seek assistance if there is major power loss, rough running, unusual smoke or noises, or overheating.

Should I replace the sensor first?

Not without testing. Inspect the connector and wiring and check the sensor circuits before deciding which part, if any, needs replacement.

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