P01FB: Turbocharger Outlet Pressure Sensor B Range/Performance

Turbocharger outlet pressure sensor B is a second pressure sensor at a compressor outlet – for example one per turbo on twin-turbo engines or a second measuring point; sensor A has the codes P00F8–P00FC. It is a separate family from the boost pressure sensor: GM and Ford report the pressure ahead of the throttle under the boost sensor codes P0236–P0238. No manufacturer using the sensor B codes was found; FCA documents sensor A and a second outlet sensor. P01FB is the plausibility fault: the signal is electrically valid but does not fit. After a long stop all pressures should equal barometric pressure; while running the value is compared with a pressure modelled from airflow, speed and throttle – GM flags its boost sensor at deviations of roughly 25–30 kPa.

Symptoms

• Check engine light on
• Loss of power, boost limited
• Limp mode possible

Most likely causes

• Sensor drifting or stuck
• Leaking charge air hose or blocked pressure port
• Contact resistance at the connector
• Fault in other model inputs (MAF, MAP)

What to check, in order

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

1. Check the hoses, clamps, and intercooler
2. Compare the reading with other engine data while varying the engine speed.
3. Compare commanded and actual pressure in live data
4. Check the actuator's movement
5. Check the vacuum hoses and the solenoid valve
6. Check the oil and the turbo shaft play before replacing it

Good to know

• Repair difficulty: medium
• It can trigger limp mode.
• It affects emissions.

What each character of P01FB means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• 1: Air and fuel
• FB: Specific fault in that system

Frequently asked questions

Can I keep driving with code P01FB?

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 P01FB?

The most common causes are: sensor drifting or stuck; leaking charge air hose or blocked pressure port; contact resistance at the connector.

Related codes

• P00F9Turbocharger Outlet Pressure Sensor A Range/Performance
• P01FATurbocharger Outlet Pressure Sensor B Circuit
• P01FFTurbocharger Outlet Pressure Sensor A/B Correlation
• P0236Turbocharger/Supercharger Boost Sensor A Circuit Range/Performance
• P0299Turbocharger/Supercharger A Underboost Condition

Sources

• law.cornell.edu: 13 CCR 1968.2
• static.nhtsa.gov: MC 10220897 9999
• gsi.ext.gm.com: 18OBDG03A Engine Diagnostics

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.