DTC P012D0 – Turbocharger/Supercharger Inlet Pressure Sensor Circuit High.

🚨 DTC P012D0 – Turbocharger/Supercharger Inlet Pressure Sensor Circuit High

Meaning

The ECU is seeing an abnormally high voltage from the turbocharger inlet pressure sensor.
This usually indicates a wiring issue, sensor fault, or overboost condition.

✅ Common Causes

1. Sensor signal wire shorted to 5V

2. Faulty turbo inlet pressure sensor

3. Bad wiring / loose connector / corrosion

4. Intake leak or blocked intake (rare)

5. Overboost due to:

Wastegate stuck closed

Boost control solenoid failure

Turbo vane issues (in VGT turbo)

6. ECU internal fault (rare)

🔧 Step-By-Step Diagnosis (For Workshop)

1. Check Live Data

Using scanner:

Compare Turbo Inlet Pressure Sensor reading with:

MAP sensor

Barometric pressure

Normal key-ON engine-OFF values should be near atmospheric (≈ 0.95–1.05 bar).

If sensor shows very high reading (e.g., 3–4 bar), circuit high is confirmed.

2. Inspect Sensor Connector & Wiring

Look for:

Broken wires

Sensor pin corrosion

Loose fit

Wire rubbing on engine/turbo

Do a wiggle test while watching live data.

3. Voltage Test (With Multimeter)

Sensor pins typically:

5V Reference

Ground

Signal wire (0.5–4.5V)

Check:

✅ 5V reference present
✅ Good ground
✅ Signal voltage at KOEO must be around 0.5–1.0V
❌ If >4.5V → Short to 5V or faulty sensor

4. Replace Sensor (If Fault Confirmed)

If:

Wiring OK

5V and ground OK

Signal fixed high
→ Replace the Turbo Inlet Pressure Sensor.

5. Check for Overboost (If Sensor OK)

Possible turbo system issues:

Wastegate stuck closed

VGT actuator stuck

Boost control solenoid faulty

Vacuum leaks (if vacuum-operated)

Check boost pressure with scanner while driving.

6. ECU Check

If everything else is perfect → possible ECU driver fault.

🚗 Symptoms Customers May Report

Low power/limp mode

High boost noise

Check engine light

Black smoke (sometimes)

🛠 Quick Fix Summary

Issue Fix

Short to 5V Repair wiring
Bad sensor Replace sensor
Connector corrosion Clean/repair pins
Overboost due to wastegate Free/replace actuator
Faulty boost solenoid Replace solenoid

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