P0238 Turbocharger Boost Sensor A Circuit Low

Understanding P0238 Error Code: Symptoms, Causes, and Solutions

If you own a car with a turbocharged engine, you may encounter a check engine light with a diagnostic trouble code (DTC) of P0238. This code refers to a circuit low condition in the turbocharger boost sensor A, which measures the pressure of the compressed air entering the engine. While this code doesn’t necessarily mean that your car is in critical condition, it could indicate a potential problem that needs attention. In this article, we’ll discuss what P0238 means, what signs you may notice, what causes it, and what you can do to fix it.

I. What is P0238 Error Code?

P0238 is a generic OBD-II code that indicates a low voltage or resistance in the circuit of the turbocharger boost sensor A. This sensor, also known as a manifold absolute pressure (MAP) sensor, detects the pressure of the air entering the intake manifold and sends the signal to the engine control module (ECM) or powertrain control module (PCM).

The ECM or PCM uses this data to adjust the fuel injection, ignition timing, and turbocharger boost pressure to optimize the engine performance and emissions. If the boost sensor A circuit voltage or resistance falls below the normal range, the ECM or PCM will set the P0238 code and illuminate the check engine light.

II. What are the Symptoms of P0238 Error Code?

The symptoms of P0238 code may vary depending on the severity and duration of the problem, as well as the make and model of your vehicle. Some of the common signs that you may notice include:

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  • Check engine light on
  • Reduced engine power or acceleration
  • Poor fuel economy or mileage
  • Rough idle or stalling
  • Boost pressure fluctuation or loss
  • Black smoke from the exhaust
  • Turbo lag or noise

If you experience any of these symptoms, you should not ignore them. They could indicate a serious issue that affects the safety, reliability, and efficiency of your vehicle. You may also fail an emissions test or damage other engine components if you continue to drive with the problem unresolved.

III. What Causes P0238 Error Code?

The causes of P0238 code can be numerous and complex. Here are some of the most common ones:

  • Faulty boost sensor A or wiring
  • Loose or corroded electrical connectors
  • Short or open circuit in the boost sensor A circuit
  • Malfunctioning ECM or PCM
  • Low or high battery voltage or charging system
  • Clogged or leaking air filter, intercooler, or intake manifold
  • Vacuum leaks or hoses disconnected or cracked
  • Exhaust leaks or turbine damage

To determine the root cause of the P0238 code, you may need to perform some diagnostic tests using a scan tool, a multimeter, and a vacuum gauge. You may also consult a professional mechanic or use online resources to get more information about your specific car model and its common issues.

IV. What are the Solutions for P0238 Error Code?

The solutions for P0238 code depend on the underlying cause and the severity of the problem. Here are some of the most effective remedies:

  • Inspect and repair or replace any damaged or loose wiring or connectors in the boost sensor A circuit.
  • Check and clean or replace the boost sensor A or MAP sensor if it’s faulty or contaminated.
  • Check and replace any clogged or damaged air filters, intercoolers, intake manifolds, or hoses that affect the air flow and pressure.
  • Check and repair any vacuum leaks or hoses that affect the intake or exhaust systems.
  • Check and repair any exhaust leaks or turbine damage that affect the boost pressure.
  • Charge or replace the battery or alternator if the voltage or charging system is low or high.
  • Reset the ECM or PCM by disconnecting the battery or using a scan tool.

Before attempting any of these solutions, you should consult your car manual, follow the safety precautions, and use the appropriate tools and techniques. You may also need to perform an OBD-II readiness test or drive cycle to ensure that the code doesn’t reappear.

V. Conclusion

P0238 is a code that signals a problem in the turbocharger boost sensor A circuit, which affects the engine performance and emissions. By understanding what causes this code, what symptoms it may trigger, and how to fix it, you can save time, money, and hassle in maintaining your car. Remember to use reliable sources, consult experts, and follow the guidelines to ensure that your car stays in top condition.


  1. Can I drive with P0238 code?
    You may be able to drive with P0238 code, but it’s not recommended as it may cause further damage or accidents.
  2. How much does it cost to fix P0238 code?
    The cost to fix P0238 code depends on the cause, the location, and the labor rates of the repair shop. It may range from $50 to $500 or more.
  3. Can I clear P0238 code with a code reader?
    Yes, you can clear P0238 code with a code reader, but it may reappear if the underlying problem is not fixed.
  4. What happens if I ignore P0238 code?
    If you ignore P0238 code, you may experience reduced performance, fuel economy, and emissions, as well as potential engine damage or failure.
  5. How often should I check my car for DTCs?
    You should check your car for DTCs regularly, at least once a month, using a scan tool or a code reader, to detect and fix any issues early.