P0110: Intake Air Temperature (IAT) Circuit Malfunction
Severity: low
What it means: P0110 means the engine computer sees an electrical problem in the intake air temperature (IAT) sensor circuit. This sensor tells the computer how cold or warm the incoming air is so it can adjust fuel. On many cars the IAT sensor is built into the mass air flow sensor, so the two codes often show up together.
Safe to drive? Usually safe to drive short-term. The computer substitutes a default value, but drivability and fuel economy can suffer.
Common symptoms
- Check engine light
- Possible hard starting or rough running
- Often stored together with P0100
Likely causes, ranked
- Loose or unplugged sensor connectorDIY
- Damaged wiringShop
- Failed IAT sensor (or MAF sensor if built in)DIY
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Vehicle-specific notes
- 2000–2005 Toyota Echo: On Car Talk, a 2000 Echo owner set P0110 along with P0100 after cleaning the MAF sensor and not fully reconnecting it. Read the full answer · Source
DIY or shop?
Usually DIY: check the connector first. Sensor replacement is simple on most cars.
Before you replace parts
- Check the sensor connector (on the MAF sensor if it is built in).
- Inspect the wiring for damage.
- Clear the code and recheck.
- Test the sensor resistance or live reading before replacing parts.
Safety / mechanic note
Verify with a mechanic. Low risk by itself, but fix it so it does not hide other problems. A code points to a circuit or system, not always a specific part.
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