P0113 Code: Intake Air Temperature (IAT) Sensor 1 Circuit High Input – Causes, Symptoms, Diagnosis & Repair
P0113 is a generic OBD-II Diagnostic Trouble Code (DTC) that indicates the Engine Control Module (ECM) has detected an abnormally high voltage signal from the Intake Air Temperature (IAT) Sensor 1 circuit. Although the engine may continue running, incorrect intake air temperature readings can affect fuel delivery, ignition timing, emissions, and overall engine performance.
This Hub guide explains the meaning of the P0113 code, common symptoms, possible causes, sensor operation, and professional diagnostic procedures. You can also browse our complete P Code Library, learn about automotive Sensors, understand diagnostic Acronyms, and improve troubleshooting using Live Data.
What Does the P0113 Code Mean?
DTC P0113 stands for Intake Air Temperature Sensor 1 Circuit High Input.
The ECM constantly monitors the temperature of the air entering the engine through the Intake Air Temperature (IAT) sensor. Intake air temperature is an important parameter used to calculate:
- Fuel injector pulse width
- Ignition timing
- Cold-start enrichment
- Emission control strategies
- Engine load calculations
If the ECM receives a voltage signal that remains higher than the normal operating range, it interprets the condition as an electrical fault and stores DTC P0113 while illuminating the Check Engine Light.
How the Intake Air Temperature Sensor Works
The Intake Air Temperature sensor is an NTC (Negative Temperature Coefficient) thermistor. As air temperature changes, the sensor resistance changes accordingly.
❄️ Cold Air → High Resistance → High Signal Voltage
🔥 Warm Air → Low Resistance → Low Signal Voltage
The ECM supplies a regulated 5-volt reference circuit and monitors the returning voltage signal. If the signal remains excessively high—commonly due to an open circuit, disconnected sensor, or wiring fault—the ECM sets the P0113 code.
Typical IAT Sensor Location
The Intake Air Temperature sensor location varies depending on the vehicle manufacturer.
- Mounted inside the Mass Air Flow (MAF) sensor
- Installed in the air intake tube
- Located in the intake manifold
- Positioned near the throttle body
Many modern vehicles integrate the IAT sensor into the MAF sensor assembly. Learn more about these components in our Sensors Library.
Typical Sensor Circuit
+5V Reference
│
▼
┌─────────────────┐
│ ECM │
│ │
Signal◄─────────────────┤
Ground──────────────────┤
└───────┬─────────┘
│
▼
Intake Air Temperature
(IAT Sensor)
│
Incoming Air
Signal Flow
Incoming Air
│
▼
IAT Sensor
│
▼
Voltage Signal
│
▼
ECM
│
▼
Fuel + Ignition Calculations
│
▼
Engine Performance
Common Symptoms of P0113
- Check Engine Light illuminated
- Reduced engine performance
- Poor fuel economy
- Hard starting during cold weather
- Rough idle
- Rich air-fuel mixture
- Black smoke from the exhaust
- Sluggish acceleration
- Higher exhaust emissions
Some vehicles may exhibit only the Check Engine Light with little or no noticeable drivability symptoms.
Common Causes of P0113
- Failed Intake Air Temperature sensor
- Disconnected IAT sensor connector
- Broken signal wire
- Open circuit
- Corroded electrical terminals
- Damaged wiring harness
- Faulty Mass Air Flow sensor (integrated IAT)
- Poor ECM connection
- ECM software issue (rare)
- ECM failure (very rare)
Severity
Most vehicles remain drivable with a P0113 code. However, prolonged driving without repair may reduce fuel economy, increase emissions, and negatively affect engine performance.
How to Diagnose the P0113 Code
Diagnosing DTC P0113 requires verifying both the Intake Air Temperature (IAT) sensor and its electrical circuit. Follow these steps before replacing any parts.
- Connect an OBD-II scan tool and confirm P0113.
- Check for additional diagnostic trouble codes.
- Review Freeze Frame Data.
- Inspect the IAT sensor connector for loose or corroded terminals.
- Inspect the wiring harness for cuts, broken wires, or rodent damage.
- Monitor Live Data while the engine is cold.
- Compare the IAT reading with the outside air temperature.
- Verify the 5-volt reference circuit using a digital multimeter.
- Check the sensor ground circuit.
- If the IAT sensor is integrated into the MAF sensor, inspect the complete MAF assembly.
If the scan tool displays approximately -40°C (-40°F), the ECM usually detects an open circuit or disconnected sensor. This is one of the most common causes of P0113.
Typical Live Data Values
Using Live Data is often the fastest way to confirm whether the IAT sensor is operating correctly.
| Condition | Typical Reading |
|---|---|
| Cold engine | Near ambient temperature |
| Warm engine | 20–40°C above ambient |
| Open circuit | Approximately -40°C |
| Short circuit | Above 130°C |
Typical Pinout
IAT Sensor Connector
┌─────────────┐
Pin 1 │ 5V Reference│
Pin 2 │ Signal │
Pin 3 │ Ground │
└─────────────┘
*Pin configuration may vary by manufacturer.
Oscilloscope / Voltage Pattern
Normal Signal
Voltage
5V ───────╲
╲
╲____
0V________________________
Voltage changes smoothly as intake air temperature changes.
Open Circuit (Typical P0113)
Voltage
5V ───────────────────────────
0V____________________________
The signal remains fixed near the reference voltage because the ECM cannot detect the sensor.
Intermittent Wiring Fault
Voltage
5V ──┐ ┌──────┐
│ │ │
└───┘ └────
0V________________________
Sudden voltage spikes usually indicate loose connectors or damaged wiring.
Common Diagnostic Mistakes
- Replacing the IAT sensor before checking the wiring.
- Ignoring connector corrosion.
- Not comparing Live Data with ambient temperature.
- Overlooking a faulty MAF sensor with an integrated IAT sensor.
- Failing to verify the 5-volt reference circuit.
- Clearing the fault code before reviewing Freeze Frame data.
Recommended Diagnostic Tools
- Professional OBD-II Scan Tool
- Digital Multimeter (DMM)
- Oscilloscope
- Back Probe Test Leads
- Electrical Contact Cleaner
- Service Wiring Diagram
How to Fix the P0113 Code
The appropriate repair depends on the root cause identified during diagnosis. Always inspect the wiring and connector before replacing the sensor.
- Reconnect a loose or unplugged IAT sensor connector.
- Clean corroded electrical terminals.
- Repair or replace damaged wiring.
- Replace a faulty Intake Air Temperature (IAT) sensor.
- Replace the Mass Air Flow (MAF) sensor if the IAT sensor is integrated.
- Repair damaged wiring harnesses.
- Update the ECM software if recommended by the manufacturer.
- Clear the DTC and perform a road test to verify the repair.
Estimated Repair Cost
| Repair | Estimated Cost (USD) |
|---|---|
| IAT Sensor Replacement | $30–$150 |
| Connector Repair | $20–$80 |
| Wiring Repair | $50–$200 |
| MAF Sensor Replacement | $100–$400 |
| Professional Diagnosis | $80–$150 |
Can You Drive With P0113?
Yes, in most cases the vehicle remains drivable. However, driving for an extended period without repairing the fault may result in poor fuel economy, increased emissions, rough cold starts, and reduced engine performance.
Repairing the issue as soon as possible helps restore accurate fuel calculations and prevents unnecessary engine performance problems.
Related Trouble Codes
The P0113 code may appear together with other intake air temperature circuit faults.
- P0110 – Intake Air Temperature Sensor Circuit
- P0111 – Intake Air Temperature Sensor Range/Performance
- P0112 – Intake Air Temperature Sensor Circuit Low Input
- P0114 – Intake Air Temperature Sensor Circuit Intermittent
Related Resources
- Browse All P Codes
- Automotive Sensors
- Live Data Guides
- Auto Parts Library
- Engine Problems
- Automotive Acronyms
Frequently Asked Questions (FAQ)
Can a bad battery cause P0113?
Not directly. However, low system voltage or electrical problems may occasionally lead to incorrect sensor readings.
Will P0113 clear itself?
If the problem is temporary, the code may become inactive after several successful drive cycles. Permanent faults require repair before the code will clear.
Can I replace the IAT sensor myself?
Yes. On many vehicles the IAT sensor is easy to access and can be replaced using basic hand tools. If it is integrated into the MAF sensor, the complete assembly may need replacement.
Can a faulty MAF sensor trigger P0113?
Yes. Many modern vehicles combine the IAT sensor with the MAF sensor. A failure inside the MAF assembly or its wiring can set the P0113 diagnostic trouble code.
Is P0113 an emissions-related code?
Yes. Incorrect intake air temperature information affects fuel calculations and may increase exhaust emissions or cause an emissions inspection failure.
Final Thoughts
The P0113 trouble code indicates that the ECM has detected a high input signal from the Intake Air Temperature sensor circuit. In most cases, the cause is a disconnected connector, damaged wiring, an open circuit, or a faulty IAT sensor.
Before replacing any components, verify the sensor connector, inspect the wiring harness, compare Live Data values with ambient temperature, and confirm the 5-volt reference circuit. A systematic diagnosis can prevent unnecessary parts replacement and reduce repair costs.
For more professional diagnostic guides, browse our complete P Code Library, explore our Sensors collection, learn common Engine Problems, and improve your troubleshooting skills with our Live Data guides.