Fuel and air

P01FC — Turbocharger Outlet Pressure Sensor B Circuit Low

Severity: medium Drive with care, to a shop

What P01FC means

The engine control module monitors air pressure at the turbocharger outlet through sensor B and uses it to control boost. P01FC sets when the sensor signal voltage falls below the expected range. The cause is most often the sensor or its wiring, and less often a real boost problem.

Symptoms

  • Check Engine Light on
  • Reduced power and sluggish acceleration
  • Erratic or incorrect boost
  • Limp mode with limited power
  • Possible unusual turbo noise
  • Hesitation when pressing the accelerator

Possible causes

  1. Failed turbocharger outlet pressure sensor B
  2. Open circuit, short to ground or damaged wiring
  3. Corroded or loose connector terminals
  4. Leak in the charge-air system or vacuum lines
  5. Sticking variable geometry mechanism
  6. Faulty turbo actuator or position sensor
  7. Mechanical turbocharger failure

How to diagnose

  1. Read all codes and freeze frame data, clear the code and see if it returns
  2. Inspect the sensor, connector and harness for chafing, heat damage, oil and corrosion
  3. Check live sensor reading with the engine off and compare it to ambient pressure
  4. Compare specified and actual boost under load
  5. Test sensor power, 5 V reference and ground at the connector
  6. Check the signal wire for opens and shorts to ground
  7. Inspect hoses, intercooler, clamps and vacuum lines for leaks
  8. Check actuator movement through its full range for sticking

Common fixes

  • Replace pressure sensor B
  • Repair the wiring or replace damaged connectors
  • Fix the charge-air or vacuum leak
  • Replace or repair the turbo actuator
  • Repair or replace the turbocharger

Questions and answers

What does P01FC mean?

It means the circuit for turbocharger outlet pressure sensor B is reading low. The ECM receives a voltage below normal and can't control boost accurately.

Can I drive with P01FC?

Only a short distance, such as to a shop. Power will probably be limited, and driving for long may harm the turbo.

Do I always need to replace the sensor?

No. Check the wiring, connector and air leaks first, since they often cause a low signal. Replace the sensor if the circuit is good and the readings are wrong.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.