Faulty or drifting turbocharger outlet pressure sensor (A or B); Damaged wiring, poor connector contact or corrosion in a sensor circuit (signal, reference or earth); Blocked, split or loose pressure sensing hose or pipe, where fitted; Boost leak or restriction between the turbocharger and the sensors causing a real pressure difference; Sensor supply voltage or earth fault affecting one or both sensors; Turbocharger or boost control fault (such as actuator or wastegate problem) producing abnormal pressure; Engine control unit fault or outdated calibration, only if confirmed by the manufacturer.

P01FF

Turbocharger Outlet Pressure Sensor A/B Correlation.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
1: AreaFuel and air metering
FF: FaultThe specific fault in that area

What it means

P01FF means the engine control unit has compared the readings from two turbocharger outlet pressure sensors (A and B) and found they do not agree within the expected tolerance. The control unit uses these signals to manage boost, so a mismatch makes it unsure which reading to trust. Which sensor is A and which is B, and where they sit, depends on the model and engine.

Symptoms

Engine warning light on
Reduced power or limp mode
Poor or inconsistent boost response
Hesitation or surging under acceleration
Possible turbo-related fault codes alongside this one

Possible causes

Faulty or drifting turbocharger outlet pressure sensor (A or B)likely
Damaged wiring, poor connector contact or corrosion in a sensor circuit (signal, reference or earth)likely
Blocked, split or loose pressure sensing hose or pipe, where fittedpossible
Boost leak or restriction between the turbocharger and the sensors causing a real pressure differencepossible
Sensor supply voltage or earth fault affecting one or both sensorspossible
Turbocharger or boost control fault (such as actuator or wastegate problem) producing abnormal pressurerare
Engine control unit fault or outdated calibration, only if confirmed by the manufacturerrare

How to diagnose

Read all stored and pending codes and the freeze frame data, noting load, engine speed and boost at the time the fault set.
Look at live data for both sensors at key-on engine-off; they should read close to each other and to ambient pressure.
Visually inspect the sensors, connectors, wiring and any sensing hoses for damage, oil contamination, chafing, water ingress or looseness.
Check the intercooler pipes, clamps, hoses and intake system for leaks, splits or restrictions.
Compare both sensor readings with engine running and under load; identify which one deviates from expected boost.
Check each sensor's supply voltage, earth and signal wiring for continuity, shorts and voltage drop, using the manufacturer's wiring data.
Perform a boost leak test and check turbo actuator operation as per the manufacturer's procedure for the engine.
Check for relevant technical service bulletins or calibration updates for your model before replacing the control unit.

How to fix

Replace the sensor that is confirmed faulty or out of range.
Repair or replace damaged wiring, terminals or connectors, and clean or reseat contacts.
Replace blocked, split or perished sensing hoses, and refit them securely.
Repair any boost leaks or restrictions in the charge air system.
Repair or replace the turbocharger or its control actuator if testing shows it is causing the pressure error.
Apply a manufacturer calibration update only where it is a documented fix for this fault.

Can I keep driving?

Medium severity

The car may be driven carefully for a short time, usually in reduced-power mode, but get it checked soon. Prolonged driving with incorrect boost control risks further turbo or engine problems.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.