P112D BUICK – Intake Air Temperature Sensor 3 Circuit High Voltage

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🔧 P112D BUICK Code: Causes, Symptoms, and Solutions

📌 Definition of P112D BUICK Code

The error code P112D indicates a problem with the Intake Air Temperature Sensor (IAT). The PCM (Powertrain Control Module) detects that the IAT sensor value is outside the manufacturer’s specified range.


🚨 Possible Symptoms

  • 🔥 Engine light on (Check Engine)
  • 🚗 Unstable idle or engine stalling
  • Poor fuel consumption
  • 🌡️ Reduced engine performance

⚠️ Possible Causes of P112D Code

🔍 Main causes include:

  1. Faulty Intake Air Temperature Sensor (IAT)
  2. Damaged IAT sensor wiring harness (shorted or open)
  3. Poor electrical connection in the IAT sensor circuit

🛠️ How to Fix P112D BUICK Code?

1️⃣ Visually inspect the wiring harness
🔎 Check the IAT sensor connectors and wires.
✅ Look for broken, melted, corroded, or disconnected wires.

2️⃣ Test the air temperature sensor with a multimeter
🔧 Measure the IAT sensor resistance at different temperatures:

  • At 20°C, resistance should be around 2,500 Ω.
  • At 50°C, it should drop to approximately 700 Ω.

3️⃣ Scan for codes with an OBD-II tool
📊 Use an OBD-II scanner to check for other error codes.

4️⃣ Clear codes and test the vehicle
🚗 If the problem persists after repairs, replace the IAT sensor.


📌 Conclusion

The P112D BUICK code is usually caused by a faulty IAT sensor or an electrical connection issue. Checking the wiring harness, performing a resistance test, and using an OBD-II scan will help diagnose and resolve the problem.

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