P0241: Turbo boost (manifold pressure) sensor B signal is too low
Turbo boost sensor B circuit low
Severity: Severity not verified — if the car runs badly, have it inspected
The sources read (TroubleCodes.net and the Delaware DMV list) define the code but do not rate how urgent it is. Loss of boost power is possible, so have it checked.
P0241 in short
P0241 means the engine computer sees a signal from boost (manifold pressure) sensor B that is too low. TroubleCodes.net lists wiring, the sensor itself and, less often, the computer as the probable causes. Which sensor is B depends on the vehicle, so confirm it in the service manual.
Turbocharged engines use a pressure sensor to tell the computer how much boost the turbo is making. Sensor B is the second one, and the computer sets P0241 when its signal voltage sits below the expected range.
TroubleCodes.net names a wiring short to ground, the sensor, or the computer as probable causes. It has no detailed guide for this code yet, so the order of checks here is general, not from a maker's procedure.
Most likely causes
These are general causes for this code across vehicles. None is specific to one make or model.
Cause 1: Wiring or connector fault in the sensor circuit
Possible — needs testing- Why it ranks here
- TroubleCodes.net lists the wiring first, and wiring is the cheapest thing to check before replacing a part.
- What would change this
- Rises if the harness is chafed, corroded or loose. Falls if the wiring tests clean.
Cause 2: Failed boost (MAP) sensor B
Possible — needs testing- Why it ranks here
- The sensor is named as a probable cause for this code, but only after the wiring is cleared.
- What would change this
- Rises if wiring and supply voltage are good and the signal stays out of range. Falls if a known-good sensor reads normally.
Cause 3: Engine computer fault
Possible — needs testing- Why it ranks here
- Listed as a possible cause but uncommon, so it ranks last.
- What would change this
- Rises only after the sensor and wiring are cleared.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: Read all stored codes and compare the boost sensor B reading with outside air pressure with the engine off.
IfThe reading is stuck far from outside air pressure
It meansThe sensor or its wiring is suspect.
IfThe reading matches outside air pressure
It meansThe fault may be intermittent; check the connector for movement.
Step 2: Look over the sensor connector and harness for damage, corrosion or loose pins. Ask a shop to check the supply, ground and signal wires against the wiring diagram.
Warning:Probing connectors with the ignition on can short a pin to ground or power and damage the sensor or computer, so back-probe only and follow the wiring diagram.
IfDamaged or corroded wiring is found
It meansRepair it and retest.
IfWiring is good
It meansThe sensor is the next suspect.
Symptoms
- Check engine light on
- Possible loss of power or poor boost on a turbocharged engine
How to fix
Step 1: With the engine off, look over the sensor connector and the wiring leading to it for damage or a loose plug.
Step 2: Ask a shop to confirm which sensor is B on your vehicle before any part is replaced.
On your vehicle
We don't have reviewed vehicle-specific evidence for P0241 yet. The causes and tests above apply across vehicles.
Related codes
Sources and review
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error