P0238 Volkswagen Code - Turbo/Super Charger Boost Sensor 'A' Circuit High
Quick Answer
This fault code is stored in the engine control module when the actual boost pressure differs from the desired boost pressure. Common causes include Faulty Manifold Absolute Pressure Sensor, Manifold Absolute Pressure Sensor harness is open or shorted, Manifold Absolute Pressure Sensor circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P0238 Volkswagen indicates Turbo/Super Charger Boost Sensor 'A' Circuit High.
- Common causes
- Common causes include Faulty Manifold Absolute Pressure Sensor, Manifold Absolute Pressure Sensor harness is open or shorted, Manifold Absolute Pressure Sensor circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P0238 Volkswagen Description
Variable geometry turbocharger.
Most systems have a failsafe function. The turbocharger is in a position where it is unable to deliver any measurable boost pressure. When the engine starts, a depression, or vacuum, is applied to the turbocharger. This causes the vanes in the turbocharger to move to a position where maximum boost pressure can be delivered. As the boost pressure increases the depression applied to the turbocharger is reduced. This reduces the increase of boost pressure as the engine load increases. An electrical or vacuum system failure will result in a loss of boost pressure.
An over boost condition is normally caused by a malfunction within the turbocharger. This malfunction causes the vanes to become stuck in a position which causes the boost pressure to increase.
An under boost condition can be caused by a faulty turbo boost control solenoid, leaking vacuum pipes, or an electrical malfunction of the boost pressure control circuit.
If a vacuum-operated solenoid is used to control the system a blocked vent can also result in an over-boost condition.
Where a turbocharger control module is used an electrical malfunction can cause the actuator to get jammed in one position. Depending on where the actuator jams the boost pressure can be affected accordingly.
What are the Possible Causes of the DTC P0238 Volkswagen?
- Faulty Manifold Absolute Pressure Sensor
- Manifold Absolute Pressure Sensor harness is open or shorted
- Manifold Absolute Pressure Sensor circuit poor electrical connection
- Faulty Mass Air Flow (MAF) Sensor
How to Fix the DTC P0238 Volkswagen?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0238 Volkswagen code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
Need more information about the P0238 Volkswagen code?
Need more information on how to fix the P0238 Volkswagen code? Get Access to Factory Service Manuals
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Frequently Asked Questions about P0238 Volkswagen Code
1. What does the OBDII code P0238 mean for a Volkswagen?
P0238 indicates that the Turbo/Supercharger Boost Sensor 'A' circuit is experiencing a high voltage condition, suggesting a potential issue with the sensor, wiring, or related components.
2. What are the common symptoms of code P0238 in a Volkswagen?
Symptoms may include a check engine light, reduced engine power, poor acceleration, black smoke from the exhaust, and the engine going into limp mode.
3. What causes the P0238 code to trigger in a Volkswagen?
Common causes include a faulty boost pressure sensor, damaged wiring or connectors, a malfunctioning turbocharger, or a clogged air filter.
4. Can I drive with the P0238 code on my Volkswagen?
Driving is not recommended, as the vehicle may experience reduced performance, increased emissions, or potential damage to the turbocharger and engine.
5. How do I diagnose the P0238 code on my Volkswagen?
Start by inspecting the boost pressure sensor and its wiring for damage or corrosion, checking for vacuum leaks, and testing the sensor with a multimeter to verify its functionality.
6. How do I fix the P0238 code in my Volkswagen?
Repairs may include replacing the boost pressure sensor, repairing damaged wiring or connectors, cleaning or replacing the air filter, or inspecting and servicing the turbocharger.
7. Is the P0238 code related to a faulty turbocharger?
While not always the case, a malfunctioning turbocharger can cause the P0238 code if it leads to abnormal boost pressure or sensor readings.
8. How much does it cost to repair a P0238 code on a Volkswagen?
Costs vary depending on the issue, but replacing a boost pressure sensor typically costs $100-$300, while turbocharger repairs can be significantly more expensive.
9. Can a dirty air filter cause the P0238 code in a Volkswagen?
Yes, a clogged or dirty air filter can restrict airflow, potentially leading to incorrect boost pressure readings and triggering the P0238 code.
10. Do I need professional help to fix the P0238 code on my Volkswagen?
While some issues, like replacing an air filter, can be done by DIY enthusiasts, diagnosing and repairing wiring, sensors, or turbochargers may require professional expertise.
Discuss the causes and fixes for P0238 Volkswagen OBDII Code
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i
Hello . I recently replaced the map sensor and still have a problem. On my connector is 2x 5v and mass and probably 1 x2v. I checked the underpressure. And I cleaned the turbine. The fault is still constantly driving up to 3000 revolutions. The cables also look good. I do not know what else I can do. In general the turbo does not turn on. help!!! -
Let me check if I can find an image. What model, year, engine is your VW?
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Here is the only images I got from the factory service manual. I hope that helps
Click here to enlarge image
Click here to enlarge image
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