Turbocharger Inlet Pressure Sensor Circuit Low
The P012C code indicates that the Engine Control Module (ECM) has detected a low voltage signal from the turbocharger/supercharger inlet pressure sensor, which is located downstream of the throttle valve. This sensor monitors the pressure in the intake system after the throttle plate. A low voltage reading typically means the sensor is reading lower than expected pressure, which can be caused by a faulty sensor, wiring issues, or a vacuum leak. This can lead to incorrect fuel and boost control, affecting engine performance.
01. Most Common Causes
- Faulty turbocharger/supercharger inlet pressure sensor
- Open or shorted wiring in the sensor circuit
- Poor electrical connection at the sensor connector
- Vacuum leak downstream of the throttle valve
- Failed ECM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine power or limp mode
- Poor acceleration or hesitation
- Possible black smoke from exhaust (rich condition)
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve the code and freeze frame data.
Step 2: Visually inspect the sensor and wiring for damage, corrosion, or loose connections.
Step 3: Test the sensor's voltage reference and ground circuits with a multimeter.
Step 4: Compare the sensor's signal voltage to manufacturer specifications (typically 0.5-4.5V).
Step 5: If sensor is suspect, replace it and clear the code; test drive to verify repair.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as the vehicle may enter limp mode, reducing power and potentially causing further damage. Have it diagnosed promptly.
How much does it cost to fix?▼
The cost typically ranges from $150 to $300, including parts and labor. The sensor itself costs $50-$150, and labor is about $100-$150.