What is the P0110 Code?
The P0110 error code is a generic OBD-II code related to the powertrain. It indicates a malfunction in the Intake Air Temperature (IAT) sensor circuit, sensor 1. This code signals that the Powertrain Control Module (PCM) has detected an abnormal voltage from the IAT sensor, outside its normal operating range.
Role and Operation of the IAT Sensor
The Intake Air Temperature (IAT) sensor is a thermistor. Its electrical resistance varies depending on the temperature of the air it measures. It is typically located in the air intake duct or the intake manifold.
The PCM sends a 5-volt reference voltage to the sensor. When the air temperature changes, the sensor’s resistance varies, thus altering the signal voltage returned to the PCM. The PCM interprets this voltage to calculate the air temperature. Cold air causes higher resistance and voltage, while hot air causes lower resistance and voltage.
Symptoms of the P0110 Code
- Malfunction Indicator Lamp (MIL) illuminated on the dashboard.
- Incorrect air-fuel mixture ratio.
- Reduced engine power.
- Increased fuel consumption.
- Irregular idle.
- In some cases, no noticeable symptoms are apparent.
Possible Causes of the P0110 Code
- Faulty IAT Sensor: The sensor itself is out of service.
- Electrical Circuit Problem: Short to ground or power, open circuit, damaged wires.
- Faulty Connector: Corroded, loose terminals, or damaged connector.
- Improperly Installed Sensor: The sensor is dislodged and no longer in the airflow.
- PCM Problem: Internal failure of the control module (rare).
Diagnosis and Solutions to Fix P0110
Preliminary Checks
- Visual Inspection: Check that the IAT sensor is properly installed in its housing and that no air ducts are loose or punctured.
- Connector Check: Inspect the sensor’s electrical connector for any signs of corrosion, damage, or loose wires.
Testing with a Diagnostic Tool
- Turn the ignition on (KOEO – Key On Engine Off) with the engine cold.
- Using your diagnostic tool, compare the values of the IAT sensor and the Coolant Temperature Sensor (CTS). They should be very similar (within a few degrees).
- If the IAT value displays an extreme temperature (e.g., -40°C or +300°C), this confirms a problem.
Electrical Testing of the Sensor
- Disconnect the IAT sensor connector.
- Using a multimeter in ohmmeter mode, measure the resistance between the two pins of the sensor.
- Compare the measured value with the manufacturer’s specifications (available in a repair manual). An infinite resistance (open circuit) or zero resistance (short circuit) indicates a faulty sensor that needs replacement.
Advanced Circuit Diagnosis
If the reading is extremely high (~300°C):
- Disconnect the sensor. If the reading changes to an extremely low value (~-50°C), replace the IAT sensor.
- If the reading does not change, check for a short to ground on the signal wire using a multimeter. If there is continuity to ground, repair the wire.
If the reading is extremely low (~-50°C):
- Disconnect the sensor and check for the presence of the 5V reference and a good ground at the vehicle connector.
- If the 5V and ground are present, short the two pins of the vehicle connector. If the reading on the diagnostic tool changes to an extremely high value, replace the sensor.
- If the 5V is absent, check the circuit up to the PCM for a break.
Related DTC Codes
P0095, P0096, P0097, P0098, P0099, P0111, P0112, P0113, P0114, P0127
Conclusion and Call to Action
The P0110 code is often resolved by replacing the IAT sensor, a component that is generally inexpensive. However, a thorough check of the electrical circuit is essential to avoid replacing a component unnecessarily.
Don’t have a diagnostic tool or don’t feel comfortable with these procedures? Entrust the diagnosis to a professional mechanic. They can quickly identify and resolve the problem, ensuring your vehicle functions properly.