P023D

Manifold Absolute Pressure - Turbocharger/Supercharger Boost Sensor A Correlation

P023D is a generic OBD-II powertrain diagnostic trouble code: Manifold Absolute Pressure - Turbocharger/Supercharger Boost Sensor A 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
P023D
Group
Powertrain
System
Turbo/Boost
Severity
Warning (MIL on)
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What P023D means

Code P023D is set when the Powertrain Control Module (PCM) detects a significant discrepancy between the signal from the Manifold Absolute Pressure (MAP) sensor and the turbocharger or supercharger boost pressure sensor designated "A". These two sensors should report closely aligned pressure values under most operating conditions — the PCM compares their outputs continuously to validate accuracy. When the difference exceeds a calibrated threshold for a defined number of drive cycles, the PCM concludes that one or both sensors has drifted out of calibration or failed entirely, and stores P023D while illuminating the MIL. This code applies exclusively to forced-induction vehicles (turbocharged or supercharged). Although the MAP and boost sensor may be physically separate components or integrated into one unit depending on the application, both must agree within the PCM's programmed tolerance window. Persistent mismatches degrade fuelling accuracy, advance/retard timing calculations, and boost control logic, leading to reduced performance and potential long-term damage if left unresolved.

Common causes

Most-frequently reported root causes when P023D is logged.

  • 1
    Defective MAP sensor (drifted calibration or internal failure)
  • 2
    Defective turbocharger/supercharger boost pressure sensor A
  • 3
    Damaged, corroded, or disconnected wiring and connectors in either sensor circuit
  • 4
    Boost sensor left unplugged after air filter or intercooler service
  • 5
    Restricted or clogged intercooler reducing boost pressure to MAP sensor
  • 6
    Insufficient engine vacuum affecting MAP sensor reference
  • 7
    PCM software fault or programming error misinterpreting sensor signals

Symptoms drivers notice

MIL (check engine light) illuminated
Noticeably reduced engine power and throttle response
Excessively rich or lean fuelling causing rough running
Increased fuel consumption
Delayed or difficult cold starts

How to diagnose P023D

A typical diagnostic flow when this code is present.

  1. 1
    Connect a scan tool, retrieve stored codes and freeze-frame data, and record both MAP and boost sensor A live values to confirm the discrepancy
  2. 2
    Perform a visual inspection of both sensor connectors and harness runs for corrosion, damage, or accidental disconnection (check especially after recent air filter or intercooler work)
  3. 3
    Verify the 5-volt reference supply and clean chassis ground at each sensor connector with a DVOM
  4. 4
    Measure sensor output voltage at idle and compare against manufacturer specifications; swap sensors if both circuits pass electrical tests
  5. 5
    Inspect the intercooler for blockage or collapsed hoses that could create a false pressure differential between sensor locations
  6. 6
    Test signal circuits through to the PCM connector to rule out an open or high-resistance wire
  7. 7
    Check for relevant Technical Service Bulletins (TSBs) before condemning the PCM

Related powertrain codes

Frequently asked questions

Can I drive with P023D stored?

Short trips are generally possible, but the PCM is operating with unreliable pressure data, which degrades boost control and fuelling accuracy. Prolonged driving risks engine damage from incorrect fuelling and should be avoided.

Which sensor is more likely to be faulty — MAP or boost sensor A?

Either can be the culprit, but a disconnected or improperly seated boost sensor after recent intake or intercooler service is a very common cause. Always inspect connectors first before replacing sensors.

Will clearing the code make it go away permanently?

No. If the underlying cause is not fixed, the PCM will re-detect the discrepancy after one or more drive cycles and reset the code.

Is P023D vehicle-specific or generic?

It is a generic SAE OBD-II code that applies to any forced-induction vehicle regardless of make or model, though specific threshold values and sensor locations vary by manufacturer.

Disabling P023D in software

RaceTune can permanently disable P023D — 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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