P1110
GMIntake Air Temperature (IAT) Sensor Circuit Malfunction (Open or Short). This is a manufacturer-specific code for GM vehicles.
Medium SeverityThis code indicates an electrical issue within the Intake Air Temperature (IAT) sensor circuit, meaning the engine computer is not receiving accurate data about the temperature of the air entering the engine. This can lead to incorrect fuel mixture calculations, potentially affecting engine performance and fuel efficiency.
⚠️ Before You Begin (Safety First)
Always wear appropriate personal protective equipment, such as gloves and eye protection. Ensure the engine is cool before working on any components. Disconnect the battery's negative terminal before performing any electrical work to prevent accidental shocks or damage to the vehicle's electrical system.
Common Symptoms
- Check Engine Light illuminated
- Poor fuel economy
- Rough idle or engine hesitation
- Reduced engine performance
- Black smoke from the exhaust (due to rich fuel mixture)
- Difficulty starting (especially in cold weather)
Common Causes
- Faulty Intake Air Temperature (IAT) sensor
- Corroded or damaged IAT sensor connector
- Open or short in the IAT sensor wiring harness
- Poor electrical connection at the IAT sensor or PCM
- Less commonly, a faulty Powertrain Control Module (PCM)
Frequently reported on: Chevrolet Silverado 2003-2007, GMC Sierra 2003-2007, Pontiac Grand Prix 2004-2008, Cadillac CTS 2003-2007, Chevrolet Trailblazer 2002-2009
Diagnostic Steps
- Locate the IAT sensor, which is typically found in the intake manifold, air intake tube, or integrated with the Mass Air Flow (MAF) sensor.
- Inspect the IAT sensor's electrical connector and wiring for any signs of damage, corrosion, or loose connections.
- Disconnect the IAT sensor's electrical connector.
- Remove the old IAT sensor, which may involve unscrewing it or releasing a clip.
- Install the new IAT sensor, ensuring it is properly seated and secured.
- Reconnect the electrical connector firmly.
- Clear the P1110 code using an OBD-II scanner.
- Start the engine and check if the Check Engine Light returns.
👨🔧 When to Call a Professional
If after replacing the IAT sensor the code persists, or if you are uncomfortable with electrical diagnosis, it's best to consult a professional mechanic. There may be a deeper wiring issue or a problem with the Powertrain Control Module (PCM).
Commonly Asked Questions
Can I drive with a P1110 code?
While your car may seem to run fine, it's not recommended to drive for extended periods with this code as it can lead to reduced fuel economy and potentially more serious engine issues over time due to incorrect fuel mixtures.
How do I test the IAT sensor?
You can test an IAT sensor using a multimeter to check its resistance at different temperatures. As the temperature increases, the resistance should decrease. Consult your vehicle's service manual for specific resistance values.
Is the IAT sensor the same as the MAF sensor?
No, while both measure air characteristics, the Intake Air Temperature (IAT) sensor specifically measures air temperature, whereas the Mass Air Flow (MAF) sensor measures the volume and density of air entering the engine. Some MAF sensors do have an integrated IAT sensor.
What if replacing the IAT sensor doesn't fix the P1110 code?
If the code persists after replacing the IAT sensor, the issue likely lies within the wiring harness leading to the sensor (an open or short circuit) or, less commonly, a problem with the Powertrain Control Module (PCM) itself.
Where is the IAT sensor located on my GM vehicle?
On many GM vehicles, the IAT sensor is integrated into the Mass Air Flow (MAF) sensor, located in the air intake tube after the air filter. On others, it might be a standalone sensor in the intake manifold or the air intake tube.