P0241🔧 Turbo/supercharger boost pressure sensingStop and fix promptly

P0241: Turbocharger/Supercharger Boost Sensor B Circuit Low (Meaning, Causes, Fixes)

Reviewed 2026-10-26 · Based on 2 cited source(s)

What P0241 means

On a turbocharged or supercharged engine, the powertrain control module (PCM) watches boost pressure with a pressure sensor (OBD-Codes.com calls it the manifold absolute pressure, or MAP, sensor). The PCM sends the sensor a 5 volt reference and gets back a voltage that rises with boost. The PCM controls boost with the boost control solenoid and uses the sensor to check that the boost is correct. OBD-Codes.com says P0241 sets when the PCM sees a low voltage signal, meaning low boost, while it is commanding high boost through boost control solenoid "B". RepairPal describes it more simply as the PCM detecting an incorrect signal from the boost pressure sensor. OBD-Codes.com calls it a generic code for all turbocharged or supercharged vehicles and names Audi, Nissan, Mitsubishi, Mazda and VW as examples. The sources' cause lists differ: OBD-Codes.com names the boost sensor, turbo, PCM and wiring, and says wiring near the turbo is the usual culprit, while RepairPal adds an exhaust leak and a brake booster pressure sensor failure, which OBD-Codes.com does not mention. P0241 is the B-sensor counterpart of P0237 (sensor A circuit low). P0239 and P0240 are the other sensor B codes and P0242 is its circuit high code, per RepairPal's code list.

Severity: can I keep driving?

Stop and fix promptly

Get it fixed before you keep driving it. RepairPal rates P0241 Urgent, meaning immediate action is needed, and says the engine may go into limp home mode. OBD-Codes.com says that because of the increased chance of catalytic converter damage and turbo overboost, it should be corrected before continuing to use the vehicle.

Common symptoms

Likely causes

Roughly most to least common, based on the sources below. Your vehicle may differ.

  1. Chafed or burnt wiring near the turbocharger causing shorts or opens; OBD-Codes.com says this is the cause more often than not (OBD-Codes.com, RepairPal)
  2. Spread or poor terminals at the boost sensor B or boost control solenoid B connectors (OBD-Codes.com)
  3. A faulty boost sensor B (OBD-Codes.com)
  4. A faulty turbocharger or supercharger (OBD-Codes.com, RepairPal)
  5. An exhaust leak (RepairPal)
  6. A brake booster pressure sensor failure (RepairPal only)
  7. A faulty PCM, which OBD-Codes.com calls the least likely cause (OBD-Codes.com, RepairPal)

Diagnostic steps you can do

⚠ Before you start

Work on a cool engine, parked on level ground with the parking brake set. Never work under a car supported only by a jack.

  1. Scan for other codes first. OBD-Codes.com says wastegate control or 5 volt reference codes can create the conditions for P0241, so fix those first.
  2. Check for technical service bulletins (TSBs) for your vehicle; there may be a known fix.
  3. Inspect the wiring near the turbo closely for chafing, melting or burns. Unplug the boost sensor B and boost control solenoid B connectors and look for spread terminals; OBD-Codes.com suggests silicone dielectric compound when reconnecting.
  4. With the key on and engine off, back-probe the sensor's reference wire with a digital multimeter. OBD-Codes.com says it should read 5 volts, and the signal wire should read between 0.2 and 0.5 volts. If not, it says to suspect the boost sensor.
  5. OBD-Codes.com then describes running the engine with the meter connected and applying vacuum to the wastegate vacuum motor with a hand vacuum pump; the sensor voltage should rise. Its procedure says to suspect the PCM if it rises and the turbo if it doesn't. Wastegate designs vary, so check your service manual before doing this test.

Typical fixes

Repair costs vary widely by vehicle, region, parts brand and shop, so we don't quote prices. Get a written estimate after diagnosis.

🛠 When to call a pro

  • The engine has very low power or goes into limp mode
  • You hear new turbo whine, grinding or see blue smoke
  • Wiring near the turbo is burnt and needs heat-resistant repair
  • You don't have a wiring diagram or a multimeter
  • The code comes back after the wiring and sensor check out

Where to buy

Plain search links. Always match parts to your exact year, make, model and engine.

OBD2 scanners on Amazon Parts at Advance Auto Parts catalog at RockAuto

FAQs

Can I drive with a P0241 code?

It's not a good idea. RepairPal rates it Urgent and says the engine may go into limp mode, and OBD-Codes.com says it should be corrected before continuing to use the vehicle because of the chance of catalytic converter damage and turbo overboost.

Is P0241 a bad boost sensor?

Sometimes, but not usually first. OBD-Codes.com says chafed or burnt wiring near the turbo causes it more often than anything else, so check the wiring and connectors and test the sensor's voltages before buying one.

What is the difference between P0237 and P0241?

Both mean the boost sensor signal is reading low. P0237 covers boost sensor A and P0241 covers boost sensor B, which engines with a second turbo or second boost sensor use.

Why do people search P0241 on Mercedes, Toyota and Mitsubishi?

P0241 is a generic code for any turbocharged or supercharged vehicle. Neither source gives a make-specific cause, so check for TSBs for your vehicle and follow the wiring and sensor checks above.

How much does it cost to fix P0241?

Neither source gives a repair cost. A wiring or connector repair is usually much cheaper than a sensor or turbo, so get a diagnosis or written estimate before buying parts.

Sources

  1. OBD-Codes.com: P0241 Turbocharger/Supercharger Boost Sensor B Circuit Low (Daniel Young, ASE Certified Master Technician)
  2. RepairPal: P0241 Turbocharger/Supercharger Boost Sensor "B" Circuit Low (rated Urgent)

Last reviewed 2026-10-26. Code definitions and repair steps can vary by manufacturer. Confirm with your vehicle's service information.