What Does P023D Mean?
The ECM has detected a correlation error between the manifold absolute pressure (MAP) sensor and the turbocharger/supercharger boost pressure sensor 'A'. These two sensors should agree within a calibrated range, but their readings are diverging. The driver may experience erratic boost control, reduced power, or the engine running in a limp/safe mode with limited boost.
Common Causes
30%
Faulty MAP sensor providing inaccurate readings
25%
Faulty boost pressure sensor 'A' providing inaccurate readings
25%
Boost leak in the intake tract between the sensors (cracked intercooler piping, loose clamp, blown hose)
15%
Clogged or restricted vacuum/pressure line to one of the sensors
5%
Wiring issue causing erroneous signal from one sensor
Diagnostic Steps
1
Compare live data PIDs for MAP sensor and boost sensor A simultaneously at idle and under light load — at idle with no boost both should read close to atmospheric pressure (approximately 98-102 kPa at sea level). Note any significant deviation.
2
Perform a boost leak test by pressurizing the intake tract to 15-20 psi with the engine off using a smoke machine or boost leak tester. Listen and look for leaks at all connections, intercooler piping, and the intercooler itself.
3
Inspect vacuum/pressure lines running to both sensors for cracks, kinks, or blockages. Blow through each line to confirm they are clear.
4
With the engine off and key on, check the voltage output of both sensors — both should read approximately 1.0-1.5V at atmospheric pressure. Compare to manufacturer specs. A sensor stuck at a fixed voltage is faulty.
5
If both sensors read correctly at idle but diverge under boost, check for a partially stuck wastegate or bypass valve that could cause unexpected pressure differentials in the intake tract.
Estimated Repair Cost
$100 - $500
Parts + labor, varies by vehicle and location
The ECM has detected a correlation error between the manifold absolute pressure (MAP) sensor and the turbocharger/supercharger boost pressure sensor 'A'. These two sensors should agree within a calibrated range, but their readings are diverging. The driver may experience erratic boost control, reduc...
The most common cause of P023D (Manifold Absolute Pressure - Turbocharger/Supercharger Boost Sensor "A" Correlation) is: Faulty MAP sensor providing inaccurate readings
Typical repair costs for P023D range from $100 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The vehicle may operate in reduced power mode. Incorrect boost control can lead to overboost (potential engine damage) or underboost (reduced performance). Drive gently and avoid heavy loads or high-speed driving until the root cause is identified and corrected.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P023D to identify the root cause.
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Quick Info
Category
Powertrain
System
Turbocharger / Supercharger System
Difficulty
Type
Generic (SAE)
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