Intake Air Temperature Sensor 1 Circuit Low

What it means

The engine computer has seen an intake air temperature (IAT) signal voltage below the lowest acceptable level. For this type of sensor, low voltage means high temperature, so the computer sees illogically hot air; the cause is usually the signal wire shorted to ground or an internal short in the sensor.

Related codes: P0110P0111P0113P0114P0117

Symptoms4

• Check engine light on.
• Very high air temperature reading on the scan tool that does not match the weather.
• Slight loss of performance or higher fuel consumption.
• Occasional hard cold starting.

Possible causes5

• Signal wire shorted to ground through damaged insulation.
• Internal short in the IAT sensor.
• Water in the connector creating an unwanted electrical path.
• Failed MAF sensor when the IAT sensor is built into it.
• Engine computer fault (rare).

How to diagnose5

1. Watch the IAT reading on a scan tool and compare it with outside air temperature.
2. Unplug the sensor with the key on; if the reading flips to the lowest value, the short is most likely inside the sensor.
3. If the reading stays high with the sensor unplugged, look for a short to ground in the signal wire.
4. Inspect the connector for water or corrosion.
5. Measure sensor resistance and compare with the manufacturer table.

How to fix5

1. Dry, clean and reconnect the connector.
2. Repair the damaged insulation on the signal wire.
3. Replace the IAT sensor if the short is internal.
4. Replace the MAF sensor if the IAT sensor is built into it.
5. Clear the codes and confirm the temperature reading is close to outside air.

The cost is low for a wire repair or a separate sensor, and rises when the sensor is built into the MAF sensor.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

Frequently asked questions