P0111
Fix within 1-2 weeksYour engine computer is seeing a problem with the signal from the sensor that measures the temperature of the air entering your engine.
Code P0111 means your engine computer detects an issue with the intake air temperature sensor signal. Common causes: Faulty IAT sensor (70%), wiring problems (20%). Drivability: Yes, safe to drive, but fix within 1-2 weeks. Repair cost: $30-$150 DIY, $100-$400 professional.
Can I Drive With P0111?
Yes, safe to drive
No restrictions, but expect reduced fuel economy and performance. Address the issue within 1-2 weeks to prevent long-term issues.
Stop driving immediately if: Flashing Check Engine Light (indicates a severe misfire, not typical for P0111 alone), significant power loss, or any unusual noises.
Symptoms of P0111
- 1Reduced fuel economy
- 2Engine hesitation or rough idle
- 3Check Engine Light (CEL) illuminated
- 4Hard starting in extreme temperatures
- 5Black smoke from exhaust (indicating a rich fuel condition)
Common Causes of P0111
Parts most likely causing this code, ranked by probability
The IAT sensor itself has failed or is providing inaccurate temperature readings to the engine control module.
70% of P0111 cases are fixed by replacing this part
Damaged wires, corroded pins, or a loose connection to the IAT sensor can disrupt the signal.
20% of P0111 cases are fixed by repairing the wiring or connector
A severely restricted air filter or other intake blockage can affect airflow and indirectly impact IAT sensor readings, especially if the IAT is integrated into the MAF sensor.
5% of P0111 cases are fixed by addressing intake restrictions
A faulty engine control module can incorrectly interpret or process the IAT sensor signal, though this is a rare cause.
5% of P0111 cases are fixed by replacing the ECM/PCM
Check These First (Before Buying Parts)
- Visually inspect the IAT sensor's electrical connector for any visible damage, corrosion, or loose connections.
- Check your engine's air filter for cleanliness and replace if it is dirty or restricted.
- Clear the code with an OBD-II scan tool and see if it returns after driving.
How to Diagnose P0111
- 1Visually inspect the IAT sensor and its electrical connector for any visible damage, corrosion, or loose connections.
- 2Check the engine's air filter for cleanliness and replace if it is dirty or restricted.
- 3Use an OBD-II scan tool to monitor the IAT sensor's live data. Compare the reading to the ambient air temperature when the engine is cold. They should be very close.
- 4Test the IAT sensor's resistance with a multimeter and compare it to the specifications in your vehicle's service manual.
- 5Check for continuity and proper voltage at the IAT sensor connector and between the sensor and the Engine Control Module (ECM).
P0111 on Popular Vehicles
Honda Civic
2006-2015The IAT sensor is often integrated into the Mass Air Flow (MAF) sensor on these models. If the IAT fails, the entire MAF sensor needs replacement.
70% fixed by replacing the MAF sensor (which includes the IAT)
Ford F-150
2004-2014IAT sensor can be a standalone unit or integrated into the MAF sensor depending on the engine. Wiring issues due to engine bay heat and vibration are common.
70% fixed by replacing IAT/MAF, 20% by wiring repair
Toyota Camry
2002-2011Similar to Honda, the IAT sensor is frequently integrated into the MAF sensor on these models. Cleaning the MAF sensor with specialized cleaner can sometimes resolve intermittent P0111 codes before full replacement.
70% fixed by replacing the MAF sensor (which includes the IAT)
Frequently Asked Questions
What does P0111 mean?
P0111 indicates that your vehicle's engine control module (ECM) has detected a problem with the signal from the Intake Air Temperature (IAT) sensor, specifically that its reading is out of the expected range or performance.
Can I drive with P0111?
Yes, you can drive safely with a P0111 code. The engine will likely run in a 'limp mode' or use a default temperature value, which can reduce fuel economy and performance, but it will not cause immediate damage. Fix this within 1-2 weeks.
Will P0111 clear itself?
No, P0111 will not clear itself. The engine control module stores this code until the underlying problem with the IAT sensor or its circuit is resolved. You will need to fix the issue and then clear the code with a scan tool.
How do I fix P0111 myself?
Start by visually inspecting the IAT sensor and its connector for damage or corrosion. If it looks good, use a scan tool to check live data. If the sensor reading is inaccurate, replace the IAT sensor. If the IAT is integrated into the MAF sensor, you may need to replace the MAF sensor or clean it with MAF cleaner.
How much does it cost to fix P0111?
The cost to fix P0111 yourself ranges from $30 to $150 for the part, depending on if it's a standalone IAT sensor or integrated into the MAF sensor. A professional repair typically costs $100 to $400, including parts and labor.
P0111 keeps coming back - why?
If P0111 keeps returning, it indicates the root cause was not fully addressed. This often points to a persistent wiring issue, a faulty connector, or a rare ECM problem. Ensure you checked for corrosion, wire damage, and verified the new sensor's readings with a scan tool.
Will P0111 fail emissions/smog test?
Yes, P0111 will cause your vehicle to fail an emissions or smog test. An illuminated Check Engine Light (CEL) due to this code is an automatic failure in most jurisdictions, and the underlying issue can lead to increased emissions.
What's the difference between P0111 and P0113?
P0111 indicates a general range or performance problem with the IAT sensor circuit, meaning the signal is inconsistent or outside expected parameters. P0113 specifically means the IAT sensor circuit has a 'High Input,' typically indicating an open circuit or a sensor reporting extremely cold temperatures.
P0111 on Honda Civic?
On many Honda Civic models, especially 2006-2015, the IAT sensor is integrated into the Mass Air Flow (MAF) sensor. This means if the IAT sensor is faulty, you will need to replace the entire MAF sensor assembly, which is a more expensive part than a standalone IAT sensor.
Questions to Ask Your Mechanic
Did you check the IAT sensor's live data with a scan tool and compare it to the actual ambient temperature when the engine was cold?
Good answer: Yes, I monitored the IAT live data. When cold, it read X degrees, which was significantly different from the ambient temperature of Y degrees. This confirms the sensor is faulty.
What did you find when you inspected the IAT sensor connector and wiring for corrosion or damage?
Good answer: I thoroughly inspected the connector and wiring. There was no visible corrosion or damage, and I verified continuity and proper voltage at the sensor harness.
Repair Cost Estimate
DIY Repair
Parts only
$30-$150
Shop Repair
Parts + labor
$100-$400
Save $70-$250 by doing it yourself
Difficulty
beginner
Time
0.5-1.5 hours
Beginner-friendly for standalone IAT sensors, Intermediate if integrated with the MAF sensor due to potentially higher part cost and more careful handling.
Cost of Waiting
Ignoring P0111 leads to reduced fuel economy, poor engine performance, and increased emissions. While not immediately catastrophic, prolonged rich running conditions can eventually damage your catalytic converter, turning a $50 sensor fix into a $1,200-$2,500 converter replacement.
While You're In There...
If the air filter is dirty, it can contribute to inaccurate air readings and is a common maintenance item that is easy to replace when accessing the intake system.
If the IAT sensor is integrated into the Mass Air Flow (MAF) sensor, cleaning the MAF sensor can sometimes resolve the issue and is a low-cost preventative measure.
Tools You'll Need
- OBD-II scan tool
- Screwdriver set
- Socket set
- Multimeter (for advanced diagnostics)
- MAF cleaner (if IAT is integrated)
P0111 is a common sensor code. Replacing the IAT sensor is a straightforward repair that restores fuel economy and engine performance without major hassle.
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Your Next Steps
Step 1: Visually inspect the IAT sensor and its electrical connector for any visible damage, corrosion, or loose connections. Also, check your air filter for cleanliness.
Step 2: If the visual inspection doesn't reveal an obvious problem, use an OBD-II scan tool to monitor the IAT sensor's live data. Compare the reading to the ambient air temperature when the engine is cold. If it's significantly off, the sensor is likely faulty.
Step 3: Parts you'll likely need: A new IAT sensor (standalone or integrated with a MAF sensor, depending on your vehicle).