Toyota Error Code P0113 – Intake Air Temperature Sensor 1 Circuit High Input

🔍 What Does Toyota Error Code P0113 Mean?

P0113 – Intake Air Temperature (IAT) Sensor 1 Circuit High Input means the ECM has detected an abnormally high voltage signal from the IAT sensor. This sensor measures incoming air temperature, which helps the engine calculate the right air-fuel mixture. A high input usually indicates the sensor is reading extremely cold temperatures (or the circuit is open), which can cause over-fueling and performance issues.

📍 When and Why It Appears

• After a cold start when the sensor wire is broken or disconnected
• When the IAT sensor circuit is open or the sensor fails internally
• After engine repairs that disturbed or disconnected the sensor
• If the wiring is corroded or damaged from heat or rodents

⚠️ Common Symptoms of P0113

• Check Engine Light (CEL) is ON
• Poor fuel economy
• Rough idle or engine hesitation on acceleration
• Black smoke from the exhaust in some cases (rich mixture)
• Hard starts, especially in warm conditions

🔎 Possible Causes of P0113

• Disconnected or loose IAT sensor harness
• Faulty Intake Air Temperature Sensor
• Broken or shorted IAT sensor wire (open circuit)
• Corroded or damaged electrical connectors
• ECM not reading signal properly due to internal issue

🧰 How to Diagnose Toyota Code P0113

1. Connect an OBD-II scanner and confirm P0113 is present
2. Read live data — if IAT reads -40°C or -40°F, it’s likely an open circuit
3. Inspect the sensor and wiring for physical damage or corrosion
4. Check resistance of the IAT sensor with a multimeter (usually 2K–5K ohms cold)
5. Backprobe sensor voltage to confirm circuit response when cold vs. warm

🔧 How to Fix Toyota Error Code P0113

1. Reconnect or repair the IAT sensor wiring harness if loose or open
2. Replace the Intake Air Temperature Sensor if it tests out of spec
3. Clean the sensor and air intake if dust or oil buildup is affecting accuracy
4. Reset the code and monitor live data during a warm-up cycle

💰 Estimated Repair Costs

• IAT Sensor Replacement: ₱800 – ₱2,000
• Wiring Harness Repair: ₱500 – ₱1,500
• Diagnostics and Labor: ₱1,000 – ₱2,000

🧠 Expert Tips

• The IAT sensor is often part of the MAF sensor — if so, replacing the MAF will also resolve this code
• If you see both P0113 and MAF-related codes (like P0101 or P0102), prioritize MAF inspection
• Wrap exposed wires in heat-resistant tape if located near the engine or exhaust

❓ FAQ – Toyota P0113

Can I drive with code P0113?

Can a dirty air filter cause this code?

Do I need to replace the ECM?

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