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Diesel particulate filter (DPF)

P2038 Reductant air pressure sensor: reading or operation not right ("A")

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P2038 means: Reductant air pressure sensor: reading or operation not right ("A"). The AdBlue (SCR) system sprays a urea solution into the exhaust to reduce nitrogen oxides. Drive gently and have the car checked soon. The repair usually costs about €100–1500 in Estonia. The most common cause: adBlue low or poor quality.

Is it safe to drive?Get it checked soonDrive gently and have the car checked soon.
Typical repair cost€100–1500parts and labour in Estonia

What it means

The AdBlue (SCR) system sprays a urea solution into the exhaust to reduce nitrogen oxides. The computer found a fault in the AdBlue quantity, quality, pump, injector or NOx sensor. There is a signal, but the reading or operation isn't plausible. The cause may be the part itself or a real mechanical fault.

What you may notice

  • AdBlue warning on the dashboard
  • A countdown of km left before the car won't restart
  • Engine light on

What could be wrong

  1. 1AdBlue low or poor quality
  2. 2AdBlue injector blocked by crystals
  3. 3Faulty AdBlue pump or heater
  4. 4Faulty NOx sensor

Repair difficulty: Moderate

What you can check yourself

Check the AdBlue level and only fill with certified AdBlue. Don't ignore the warning: eventually the car won't start. You can check the simple things yourself, but the repair is best done in a workshop.

How we fix it

  1. We check AdBlue quality and quantity
  2. We test the pump, injector and heater
  3. We check the NOx sensors
  4. We replace the faulty part

Standard SAE description: Reductant Injection Air Pressure Sensor "A" Circuit Range/Performance

This code usually comes with: Diesel particulate filter (DPF) lightSee what the light means →

Want a definite answer?

Bring the car to our workshop in Estonia for diagnostics. We read the fault codes, test the sensors and tell you what is wrong. Repair price depends on the work involved, generally €45 per hour.

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Questions

What does fault code P2038 mean?

Reductant air pressure sensor: reading or operation not right ("A"). The AdBlue (SCR) system sprays a urea solution into the exhaust to reduce nitrogen oxides. The computer found a fault in the AdBlue quantity, quality, pump, injector or NOx sensor. There is a signal, but the reading or operation isn't plausible. The cause may be the part itself or a real mechanical fault.

Can I drive with code P2038?

Drive gently and have the car checked soon.

How much does it cost to fix P2038?

Roughly €100–1500 in Estonia. The price depends on exactly what has failed and on the car.

How is P2038 fixed?

We check AdBlue quality and quantity. We test the pump, injector and heater. We check the NOx sensors. We replace the faulty part.

Related codes

P2039Reductant air pressure sensor: signal or voltage too low ("A")P2037Reductant air pressure sensor: circuit fault ("A")P2171Exhaust pressure regulator vent solenoid: signal or voltage too highP2201NOx sensor: reading or operation not right (bank 1)P2202NOx sensor: signal or voltage too low (bank 1)P0402Too much gas flowing through the EGR valveP0033Turbo bypass valve: circuit fault

Based on AI combined with our hands-on workshop experience and knowledge. This information is general and prices are approximate (Estonian workshop rates). The same code can mean different things on different cars. Only an inspection of the car gives a definite answer.

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