EngineLightCodes
Powertrain code

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

Severity
Fix soon
Typical repair cost
$40–$280
Do it yourself
Possible, easy
Shop time
0.5–1.5 hours

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.

How the engine computer detects it

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 (1.7 psi), with the warning light and limp mode limited to 170 Nm (125 lb-ft). 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.

Written from public technical sources and not yet checked by a mechanic. How we write these pages

Symptoms

  • Check engine light on
  • Limp mode, limited power
  • Otherwise often unremarkable

Common causes

  1. Manifold or boost sensor drifting or dirty Most likely
  2. Contact resistance at connector or ground of one sensor Possible
  3. Pressure port or hose of one sensor blocked (oil sludge, ice) Possible
  4. Engine module or reference voltage Less likely

How to diagnose P023D

  1. Read every stored code with an OBD-II scanner. If misfire or fuel trim codes are there too, fix those first: they often cause this one.
  2. Inspect the parts involved: manifold absolute pressure sensor, boost pressure sensor a, sensor wiring.
  3. Work through the causes above from most to least likely, cheapest checks first.
  4. Clear the code and drive a full drive cycle to confirm the repair held.

Reading the code

P
Powertrain
0
Generic (SAE) code
2
Fuel and air metering (injector circuit)
3D
Specific fault

Questions drivers ask

Can I drive with code P023D?

Drive gently and only as far as you need to. The engine computer may limit power to protect the engine, so avoid highways and heavy traffic until it's fixed. If the check engine light starts flashing, pull over.

Will my car pass an emissions inspection with P023D?

Probably not in states that test vehicles with an OBD-II scan: an emissions-related code that keeps the check engine light on is usually an automatic fail. Rules differ by state and county, so check yours.

Can I fix P023D myself?

Often yes, with an OBD-II scanner and basic tools. Difficulty: easy. Start with the cheapest checks before replacing expensive parts.

This page is general information, not a substitute for a professional diagnosis. Repair costs are rough estimates for parts and labor and vary by vehicle and region.