P012D: Turbocharger/Supercharger Inlet Pressure Sensor A Circuit High
What to do
Ask for the connector to be checked first, specifically that it is fully clicked home. This sensor is unplugged routinely during air filter and intake work, and one left pushed on but not latched produces exactly this code — a free fix if it is found before parts are ordered.
Mention any recent servicing or work under the bonnet, however unrelated it seems.
The car will usually still drive, though it may hold back boost and feel flat.
Expect turbocharger codes alongside, which are generally consequences of this one rather than separate faults.
What this code means
The turbocharger inlet pressure sensor signal is above the highest voltage the circuit should produce.
High and open read identically from inside the module, which is the single most useful thing to know about this code. Most pressure sensor inputs carry a weak pull-up, so a disconnected sensor leaves the module looking at its own reference voltage — indistinguishable from a wire shorted to a supply.
The measurement that separates them takes a minute and is made at the connector with the sensor unplugged. It is worth insisting on, because the two repairs have nothing in common: one is a broken connection, the other is a wire touching something it should not.
On this sensor the open-circuit case is the more likely of the two, for a practical reason. It is a small sensor on or near the intake ducting, frequently unplugged during air filter changes, intake work and diagnostics — and just as frequently left unlatched afterwards. A connector that is pushed on but not clicked home works until the next thermal cycle or speed bump.
Confirm it is actually connected before anything else. On a car that has recently been in for other work, this is a genuinely common finding and costs nothing.
Beyond that, look for a chafed wire against a bracket or the engine, and for a sensor that has failed internally open — which does happen and is the honest conclusion once the wiring is proven.
Likely causes
Start here
- Open circuit in sensor wiring · moderate
- Sensor left disconnected after previous work · easy
- Corroded or loose connector · easy
Less common
- Wiring shorted to voltage · moderate
- Faulty turbocharger inlet pressure sensor · easy
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
Sign in or create an account to add what you found about P012D.