Fault in the boost sensor B or the MAP sensor, giving a skewed or drifting signal; Damaged wiring, poor connections or corroded terminals in the sensor circuit (signal, reference voltage or earth); Boost leak in the charge air system, such as a split hose, loose clamp, or leaking intercooler or pipe joint; Blocked, oily or sooty sensor port or vacuum/pressure line to the sensor; Turbocharger control fault, such as a sticking wastegate, variable geometry mechanism or boost control valve, causing real boost to differ from what is expected; Intake restriction, such as a blocked air filter or collapsed intake pipe, affecting one sensor reading more than the other; Fault in the engine control unit or an outdated calibration, where the manufacturer has identified one as a known cause for the model.

P023E

Manifold Absolute Pressure - Turbocharger/Supercharger Boost Sensor B Correlation.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
2: AreaFuel and air metering (injector circuit)
3E: FaultThe specific fault in that area

What it means

P023E is a generic code meaning the readings from the manifold absolute pressure sensor and turbocharger/supercharger boost sensor 'B' do not agree with each other. The engine control unit compares the two signals, and sometimes other data such as barometric pressure or modelled boost, and sets the code when the difference is bigger than expected for the operating conditions. Which sensors are involved and where they sit depends on the engine.

Symptoms

Engine warning light on
Reduced power or the car going into limp mode
Poor or inconsistent acceleration under load
Boost pressure that is too high or too low on a live data reading
Hesitation or surging when the turbo is working
Possible rough running or poor fuel economy

Possible causes

Fault in the boost sensor B or the MAP sensor, giving a skewed or drifting signallikely
Damaged wiring, poor connections or corroded terminals in the sensor circuit (signal, reference voltage or earth)likely
Boost leak in the charge air system, such as a split hose, loose clamp, or leaking intercooler or pipe jointlikely
Blocked, oily or sooty sensor port or vacuum/pressure line to the sensorpossible
Turbocharger control fault, such as a sticking wastegate, variable geometry mechanism or boost control valve, causing real boost to differ from what is expectedpossible
Intake restriction, such as a blocked air filter or collapsed intake pipe, affecting one sensor reading more than the otherpossible
Fault in the engine control unit or an outdated calibration, where the manufacturer has identified one as a known cause for the modelrare

How to diagnose

Read all stored and pending codes and the freeze frame data, noting load, rpm and boost at the time the fault set
Inspect the sensor connectors, wiring and earth connections for damage, corrosion, chafing or oil contamination
Visually check the charge air system, including hoses, clamps, intercooler and pipework, for splits, oil leaks or loose joints
Check the air filter and intake ducting for blockage or restriction
With the engine off (key on), compare the MAP and boost sensor readings against each other and against barometric pressure; they should be very close
Compare live readings of both sensors, plus requested and actual boost, during a road test or under load to see which one deviates
Check the sensor supply voltage and signal circuit with a multimeter against the manufacturer's specification, and check the sensor port is clear
Pressure-test the charge air system and check wastegate or turbo actuator operation as per the model-specific procedure

How to fix

Replace the faulty MAP or boost sensor once testing shows it is out of specification
Repair or replace damaged wiring, connectors or terminals in the sensor circuit
Repair boost leaks by replacing split hoses, refitting or replacing clamps and sealing leaking intercooler or pipe joints
Clean or clear a blocked sensor port or pressure line, and fix the source of any oil or soot contamination
Repair or replace a faulty wastegate, actuator, boost control valve or variable geometry mechanism as identified by testing
Replace a blocked air filter or restricted intake component; update the control unit software only if the manufacturer lists it as a fix for this fault

Can I keep driving?

Medium severity

The car can usually be driven carefully for a short time, but power may be limited and a boost fault can get worse or stress the turbo and engine. Get it diagnosed soon, and avoid heavy loads or hard acceleration until it is fixed.

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