P025F: Turbocharger/Supercharger Boost Sensor B Intermittent/Erratic

Boost sensor B is a second boost pressure sensor, for a second turbo or bank on twin-turbo engines or a second stage. P025F counts brief excursions of its signal outside the valid range that are too short for the low or high code – the counterpart of P025E, which Ford sets after 10 such events in one drive cycle. No manufacturer using sensor B codes was found; the description follows CARB's input monitoring requirement and Ford's sensor A check.

Medium severity. Can I keep driving?Drive without demanding power and go to a repair shop soon. If you see a lot of blue smoke or hear a metallic noise, shut off the engine.

Symptoms

Check engine light on
Occasional loss of power
Boost limited

Most likely causes

Loose contact or corrosion at the sensor B connector
Wire breaking from vibration or heat
Sensor B faulty

What to check, in order

Start with the simplest. You can tick off each step.

Check the hoses, clamps, and intercooler
Gently move the wiring with the engine running and watch whether the reading changes.
Compare commanded and actual pressure in live data
Check the actuator's movement
Check the vacuum hoses and the solenoid valve
Check the oil and the turbo shaft play before replacing it

Good to know

Repair difficulty: easy
It can trigger limp mode.
It affects emissions.

What each character of P025F means

P: Powertrain: engine and transmission
0: Generic code: same on every make
2: Fuel injection
5F: Specific fault in that system

Frequently asked questions

Can I keep driving with code P025F?

Drive without demanding power and go to a repair shop soon. If you see a lot of blue smoke or hear a metallic noise, shut off the engine.

What causes code P025F?

The most common causes are: loose contact or corrosion at the sensor B connector; wire breaking from vibration or heat; sensor B faulty.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.