Intake Air Temperature (IAT) Circuit Low Input
What does this mean?
Code P0112 indicates the IAT sensor is sending an abnormally low voltage signal (indicating high temperature) to the PCM.
Disclaimer: This diagnostic code is part of the standard OBD2 system and can apply to Alfa-romeo Giulietta models manufactured from 1996 to 2026. However, please note that the presence of this specific code depends on your vehicle's exact engine configuration, options, and production year.
Common Causes
Faulty Intake Air Temperature (IAT) sensor
Damaged, chafed, or broken wiring harness
Corroded or loose electrical connector
Symptoms to Watch For
- Check Engine Light is illuminated
- Decreased fuel economy
- Rough or unstable idle
How to Diagnose
Common Solutions
Replace the Intake Air Temperature (IAT) sensor: This is the most frequent solution if the sensor itself is internally shorted, providing incorrect resistance readings, or has failed internally.
Repair or replace damaged wiring or connector: If diagnostic steps reveal a short to ground, an open circuit, or corrosion/damage within the IAT sensor's wiring harness or connector, repairing the specific section or replacing the entire connector/harness segment is necessary.
Address a short to ground in the IAT signal circuit: If the wiring tests indicate the signal wire is shorted to ground, locate and repair the short. This often involves tracing the harness carefully for chafing or damage.
Replace the Powertrain Control Module (PCM): In rare instances, if all sensor and wiring tests confirm integrity, the internal IAT circuit within the PCM itself may be faulty. This should only be considered as a last resort after exhaustive testing of the sensor and wiring.