P023DManifold Absolute Pressure - Turbocharger/Supercharger Boost Sensor A Correlation
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P023D compares the manifold pressure sensor (after the throttle) with boost sensor A (before the throttle): with the engine stopped both must read the same ambient pressure. Saab's 2.8 V6 checks this once per trip with the ignition on before starting and sets the code at a difference of more than 12 kPa, with the warning light and limp mode limited to 170 Nm. The code does not say which sensor is wrong – barometric pressure as a third value decides. Electrical faults of either sensor (P0107/P0108, P0237/P0238) block the test and must be fixed first. GM and Ford run the same comparison but report it as P0236, P0106 or P2227.
- What you may notice
- Check engine light on
- Limp mode, limited power
- Otherwise often unremarkable
- Likely causes
- LikelyManifold or boost sensor drifting or dirty
- PossibleContact resistance at connector or ground of one sensor
- PossiblePressure port or hose of one sensor blocked (oil sludge, ice)
- RareEngine module or reference voltage
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €40 – €250
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.