P023D: Manifold Absolute Pressure - Turbocharger/Supercharger Boost Sensor 'A' Correlation

Overview

P023D indicates a correlation fault between the MAP sensor and turbocharger/supercharger boost sensor A detected by the PCM in forced induction systems

Common Symptoms

• Check Engine Light (MIL) illuminated
• Decreased engine power and poor acceleration
• Reduced fuel economy
• Possible rough idle or hesitation under load

Most Common Causes

Diagnostic Steps

1. Connect a professional OBD-II scanner and retrieve current and freeze‑frame data
   Expected: Confirm P023D and note engine conditions when code set
   Interpretation: Verifies relevance and context of the fault
2. Visually inspect MAP and boost pressure sensor wiring and connectors
   Expected: No corrosion, broken wires, or loose connections
   Interpretation: Eliminates simple electrical issues
3. Use scan tool to compare live sensor data between MAP and boost pressure sensors across operating conditions
   Expected: Signals should correlate within manufacturer specs
   Interpretation: Identifies misreporting or inconsistent sensor signals
4. Check for vacuum and boost leaks using smoke test or pressure test
   Expected: No leaks in intake or boost hoses
   Interpretation: Leaking systems can skew pressure readings
5. Test sensors electrically with multimeter per OEM spec (reference voltage, ground, output)
   Expected: Correct reference and signal voltages
   Interpretation: Faulty sensors often fail these electrical tests
6. If sensors and wiring check normal, consider PCM software update or reflash per manufacturer guidance
   Expected: Resolved code after update/repair
   Interpretation: Software calibration issues can sometimes cause false correlation flags

Repair Solutions

Frequently Asked Questions