P1109: IAT - B Sensor Intermittent
MediumPowertrainEngine/Powertrain
What does P1109 mean?
P1109 is a diagnostic trouble code indicating "IAT - B Sensor Intermittent". A sensor in the engine/powertrain is reporting abnormal data or has lost communication with the ECU. Sensors can fail due to age, contamination, heat exposure, or wiring issues.
Common causes
- Faulty engine/powertrain component
- Wiring or connector issue in the related circuit
- Failed sensor providing incorrect readings
- Software/calibration issue requiring ECU update
- Related component causing secondary fault
What should you do?
Schedule a diagnostic appointment at your earliest convenience. The vehicle is generally safe to drive short distances, but the underlying issue should be addressed to prevent it from worsening.
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Code P1109 can mean different things depending on your vehicle. TorqueBot gives you a diagnosis specific to your make, model, and year.