What Does P012D Mean?
The ECM has detected that the turbocharger/supercharger inlet pressure sensor circuit downstream of the throttle valve is producing a voltage above the maximum expected threshold. This high signal indicates an open ground circuit, a short to battery voltage on the signal wire, or a failed sensor with its output floating high. The ECM sees this as an implausibly high pressure reading.
Common Causes
35%
Failed inlet pressure sensor with open internal ground causing signal to float to reference voltage
25%
Open or high-resistance ground wire in the sensor circuit caused by corrosion or broken wire
20%
Signal wire shorted to the 5V reference or battery voltage through damaged harness insulation
20%
Corroded or backed-out ground terminal at the sensor connector creating an open ground condition
Diagnostic Steps
1
Check the inlet pressure sensor voltage on a scan tool. A reading near 5V or maximum kPa confirms a high circuit condition. Disconnect the sensor; if voltage drops to near 0V at the ECM, the sensor has an internal fault.
2
With the sensor disconnected, verify that both the 5V reference and ground are present at the harness connector. If ground is missing or shows high resistance, trace the ground circuit to find the open.
3
Check for shorts between the signal wire and the 5V reference wire by measuring resistance between them at the ECM connector with the sensor disconnected.
4
Inspect the sensor connector ground terminal for corrosion, poor crimping, or a backed-out pin that is not making contact.
5
Verify the sensor wiring is not routed near high-voltage ignition components that could induce voltage on the signal wire through electromagnetic coupling.
Estimated Repair Cost
$100 - $450
Parts + labor, varies by vehicle and location
The ECM has detected that the turbocharger/supercharger inlet pressure sensor circuit downstream of the throttle valve is producing a voltage above the maximum expected threshold. This high signal indicates an open ground circuit, a short to battery voltage on the signal wire, or a failed sensor wit...
The most common cause of P012D (Turbocharger/Supercharger Inlet Pressure Sensor Circuit High (Downstream of throttle valve)) is: Failed inlet pressure sensor with open internal ground causing signal to float to reference voltage
Typical repair costs for P012D range from $100 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A stuck-high pressure reading makes the ECM believe the intake manifold has high positive pressure. The ECM may aggressively close the wastegate or reduce fueling, potentially causing under-boost, lean conditions, or limp mode that severely limits vehicle performance.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P012D to identify the root cause.
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Quick Info
Category
Powertrain
System
Turbocharger/Supercharger Boost Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
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