Fault code P0238 – a step-by-step guide to diagnosing and fixing it

The meaning of error code P0238 – Turbocharger Boost Sensor A Circuit High

P0238: Causes, signs and repairs

Error code P0238 is displayed and the check engine light is on - what does this mean?

The DTC P0238 is triggered by the OBD system when the turbocharger pressure exceeds the upper limit and is therefore too high. This EOBD fault code indicates a problem in the turbocharging system, which can lead to engine damage. For various manufacturers, this trouble code can also be referred to as "Turbocharger Boost Sensor A Circuit High".

What causes can this error code have?

Defective wastegate control unit
Blocked or damaged charge air cooler
Leaking boost pressure lines or hoses
Defective boost pressure sensor
Faulty turbocharger control flap
Clogged or blocked wastegate valve
Defective engine control unit (ECU)
Damaged wiring to the boost pressure sensor
Clogged air filter
Mechanical defect on the turbocharger

What symptoms occur in parallel with fault code P0238?

Loss of power: Significantly reduced engine power and poor acceleration
Smooth engine running: Engine runs unevenly or jerks when accelerating
Whistling noises: Unusual noises from the engine compartment, especially when accelerating
Black smoke: Dark exhaust fumes from the exhaust pipe
Increased fuel consumption: Noticeably higher consumption than usual
Emergency running program: Engine switches to emergency running mode with limited power

How can the problem with fault code P0238 be rectified?

Repairing fault code P0238 requires a systematic diagnosis of the turbocharger system.
Check boost pressure lines and hoses for leaks and replace defective parts
Test the boost pressure sensor and replace with a new component if defective
Clean or replace wastegate valve if it is blocked or defective
Check turbocharger control flap and repair or replace if necessary
Check intercooler for blockage or damage and clean or replace
Check the wiring to the boost pressure sensor for damage and repair it
Replace the air filter if it is heavily soiled
Check engine control unit for software errors and carry out updates
Replace turbocharger completely in the event of mechanical damage

FAQ - Frequently asked questions about DTC P0238

Can I continue driving with error code P0238?

Continuing to drive with code P0238 is not recommended, as excessive boost pressure can cause serious engine damage. Only drive to the nearest workshop and avoid high engine speeds.

How much does it cost to repair error code P0238?

Depending on the cause, the repair costs vary between €150 for simple hose defects and up to €3,000 for a complete turbocharger replacement. A precise diagnosis is therefore important.

How can I delete error code P0238 myself?

The DTC P0238 can be deleted with an OBD scanner, but will return if the cause has not been rectified. A professional repair is necessary.

Is fault code P0238 the same for all manufacturers?

Yes, P0238 is a standardized EOBD code that has the same meaning for all manufacturers. However, the specific repair procedures may vary.

Can a defective air filter cause the code P0238?

A heavily contaminated air filter can indeed cause problems in the turbocharger system and trigger fault code P0238, as the turbocharger has to work harder.

How long does it take to repair fault code P0238?

Depending on the cause, the repair can take between 1-2 hours for simple hose defects to a whole working day for a turbocharger replacement.

Vehicles in which error code P0238 occurs most frequently

Error code P0238 is a boost pressure error that occurs in turbocharged vehicles and indicates excessive turbocharger pressure, but occurs most frequently in the following vehicles:

Audi: A3, A4, A6, Q5, TT (2008-2018)
BMW: 320d, 520d, X3, X5, 1 Series, 3 Series (2007-2017)
Mercedes-Benz: C-Class, E-Class, GLK, Sprinter (2009-2019)
Volkswagen: Golf, Passat, Tiguan, Touran (2008-2018)
Ford: Focus, Mondeo, Kuga, Transit (2010-2020)
Opel: Astra, Insignia, Zafira (2009-2017)
Peugeot: 308, 508, 3008, 5008 (2011-2019)
Renault: Megane, Laguna, Scenic (2010-2018)
Seat: Leon, Altea, Alhambra (2009-2017)
Skoda: Octavia, Superb, Yeti (2008-2018)

If the code P0238 occurs in your vehicle, you should visit a specialist workshop immediately, as turbocharger damage can result in costly follow-up repairs. Early diagnosis can often prevent major damage to the engine and significantly reduce repair costs.

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