Powertrain, generic · Fuel and air metering

P01FF Turbocharger Outlet Pressure Sensor A/B Correlation

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

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. P01FF compares sensors A and B: with the engine off both should read barometric pressure, and in comparable operation they must agree within a tolerance. If they disagree without either being electrically faulty, this code sets; which one is wrong is found by comparing with barometric and manifold pressure. On twin-turbo engines a genuinely weaker turbo on one bank can also cause it.

Likely causes

One sensor drifting
Leak or hose damage between the measuring points or on one bank
Contact resistance at one sensor's connector or ground
Uneven turbo output (twin-turbo, wastegate or vanes on one side)

Symptoms

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

Repair estimate

DifficultyMediumDIY possible
Parts and labour€50–400
Time0.5–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

turbocharger outlet pressure sensor aturbocharger outlet pressure sensor bcharge air hoses

Related codes

P00F8P00F9P01FAP01FBP0236

References: law.cornell.edu, gsi.ext.gm.com, static.nhtsa.gov.