P023E

Manifold Absolute Pressure - Turbocharger/Supercharger Boost Sensor B Correlation

P023E is a generic OBD-II powertrain diagnostic trouble code: Manifold Absolute Pressure - Turbocharger/Supercharger Boost Sensor B Correlation. It is logged by the engine control unit when the turbo/boost monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.

Code
P023E
Group
Powertrain
System
Turbo/Boost
Severity
Warning (MIL on)
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What P023E means

Code P023E is the direct counterpart to P023D, but refers to the turbocharger or supercharger boost pressure sensor designated "B" rather than sensor "A". The PCM continuously compares this sensor's output with the Manifold Absolute Pressure (MAP) sensor reading; when the voltage signals differ by more than the programmed tolerance for the required number of drive cycles, P023E is stored and the MIL illuminates. Sensor "B" typically corresponds to a second boost sensor on a twin-turbo system, a different measurement point in the induction tract, or an alternative sensor position defined by the manufacturer. Because the PCM relies on both sensors working in agreement to set boost targets, calculate fuel trim, and manage wastegate or bypass valve position, a sustained correlation error can degrade boost control across the full operating range, resulting in inconsistent power delivery, incorrect air-fuel ratios, and in some cases activation of a protective reduced-power strategy. All diagnostic steps that apply to P023D apply equally here, with attention directed at the "B" sensor circuit.

Common causes

Most-frequently reported root causes when P023E is logged.

  • 1
    Defective turbocharger/supercharger boost pressure sensor B
  • 2
    Defective MAP sensor outputting an incorrect reference signal
  • 3
    Corroded, damaged, or loose wiring and connectors on the boost sensor B circuit
  • 4
    Restricted intercooler or collapsed charge pipe between sensor B and the MAP sensor
  • 5
    Loss of engine vacuum affecting MAP sensor accuracy
  • 6
    Boost sensor B inadvertently left disconnected after maintenance
  • 7
    PCM programming error or internal fault misinterpreting sensor B signals

Symptoms drivers notice

MIL illuminated
Reduced engine power or inconsistent boost delivery
Rich or lean running and associated rough idle
Poor fuel economy
Hesitation or surge under load on turbocharged applications

How to diagnose P023E

A typical diagnostic flow when this code is present.

  1. 1
    Retrieve codes and freeze-frame data; monitor live MAP and boost sensor B PIDs simultaneously to quantify the signal gap
  2. 2
    Inspect the boost sensor B connector and harness for corrosion, heat damage, or accidental disconnection
  3. 3
    Verify 5-volt reference and signal ground at the boost sensor B connector with a DVOM
  4. 4
    Compare boost sensor B output voltage at idle and under load against manufacturer specifications; compare with sensor A if applicable
  5. 5
    Inspect the charge air path between sensor B location and the MAP sensor for leaks, collapsed hoses, or intercooler blockage
  6. 6
    Trace signal wiring to the PCM connector to check for open circuits or excessive resistance
  7. 7
    Consult manufacturer TSBs and recalibrate or replace the faulty sensor after confirming circuit integrity

Related powertrain codes

Frequently asked questions

What is the difference between P023D and P023E?

Both describe a MAP-to-boost-sensor correlation fault. P023D involves boost sensor A and P023E involves boost sensor B. The distinction matters on engines with two boost sensors measuring pressure at different points or on twin-turbo systems.

Can a vacuum leak cause P023E?

Yes. A vacuum or boost leak between the measurement points of the MAP sensor and boost sensor B will cause their readings to diverge, triggering the correlation fault even if both sensors are electrically healthy.

Does P023E cause limp mode?

Not always, but the PCM may reduce boost targets or restrict throttle as a precaution if the error is persistent, resulting in noticeably reduced performance.

Should I replace both sensors at once?

Only if testing confirms both are out of specification. Replace the faulty sensor first, recheck live data, and only replace the second sensor if the correlation error persists after repairs.

Disabling P023E in software

RaceTune can permanently disable P023E — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.

Permanent
The monitor is disabled in the ECU itself — not just cleared. It cannot return.
Tailored to your file
Each patch is matched to your specific software version — never a one-size-fits-all file.
Reversible
The original file is always preserved. Reflash the stock to return the ECU to factory state.

Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.

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