Technical Description of OBD-II Trouble Code
Correlation between Manifold Absolute Pressure – Turbocharger/Supercharger Boost Sensor A
What does that signify?
This is a generic diagnostic trouble code (DTC) that is commonly found in OBD-II vehicles. It can be applicable to various vehicle brands such as Land Rover (Range Rover, Discovery), Ford, Chevrolet, Mazda, Dodge, Peugeot, Saab, Toyota, etc.
Although it is a generic code, the specific repair steps may vary depending on the year, make, model, and powertrain configuration of the vehicle.
If your OBD-II equipped vehicle has stored a code P023D, it means that the powertrain control module (PCM) has detected a discrepancy in the signals between the manifold absolute pressure (MAP) sensor and the turbocharger/supercharger boost sensor designated as “A”.
The designation “A” refers to a specific boost sensor in a system that may have multiple boost sensors in different locations. To determine which sensor the “A” references for your vehicle, consult a reliable source of vehicle information. This code is only applicable to vehicles equipped with forced air induction devices, such as turbochargers and superchargers.
The MAP sensor provides the PCM with a voltage signal that indicates the air density or pressure in the intake manifold. The voltage signal is received by the PCM in either kilopascal (kPa) units or inches of mercury (Hg). In some vehicle applications, the MAP sensor is used as a substitute for barometric pressure and measured in similar increments.
The turbocharger/supercharger boost pressure sensor (designated as A) is likely to have a similar design to the MAP sensor. It monitors the air density (boost pressure) inside the turbocharger/supercharger intake pipe and provides the PCM with an appropriate voltage signal.
A code P023D will be stored, and a malfunction indicator lamp (MIL) may illuminate if the PCM detects voltage signals between the MAP sensor and the turbocharger/supercharger boost sensor A that differ by more than a programmed degree. Multiple ignition cycles with a failure may be required for MIL illumination.
What is the severity of this DTC?
The conditions contributing to a code P023D can adversely affect overall engine performance and fuel efficiency. Therefore, it should be considered a severe issue.
What are some of the symptoms of the code?
Symptoms of a P023D trouble code may include:
What are some of the common causes of the code?
Possible causes for this P023D trouble code may include:
What are some P023D troubleshooting steps?
Before attempting to diagnose a code P023D, it is recommended to have access to a diagnostic scanner, a digital volt/ohmmeter (DVOM), a manual vacuum pressure gauge, and a reliable source of vehicle information. When diagnosing any MAP sensor related code, it is important to ensure that the engine is producing sufficient vacuum, which can be checked using the vacuum pressure gauge.
If there are no obstructions in the intercooler and the air filter is relatively clean, a visual inspection of all MAP/turbocharger/supercharger boost sensor system wiring and connectors should be conducted. Any necessary repairs should be made. Next, connect the scanner to the vehicle diagnostic port and retrieve all stored codes and freeze frame data. Freeze frame data provides a snapshot of the exact circumstances that were occurring at the time of the malfunction leading to the stored code P023D. It is recommended to write down this information as it may be helpful during the diagnosis. Clear the codes and test-drive the vehicle to see if the code is reset.
If the code is reset:
If all the sensors comply with the manufacturer’s specifications:
If reference voltage and a ground are present:
If the sensor signal circuit reflects the correct degree of voltage:
If all MAP/turbocharger/supercharger boost pressure sensors and circuits are within specifications, suspect PCM failure or a PCM programming error.
