The 2019 Mazda Mazda3 triggering P0113 indicates the intake air temperature (IAT) sensor circuit is reading higher than expected—typically indicating an open circuit or extremely high temperature signal.
Understanding P0113
P0113 sets when the IAT signal voltage is too high, which the ECM interprets as extremely low temperature (below -40°F typically). This usually means an open circuit rather than actual extreme cold.
IAT Sensor Function
The intake air temperature sensor measures incoming air temperature. The ECM uses this data to adjust fuel mixture—cold air is denser and requires more fuel. Inaccurate readings affect performance and emissions.
Common Causes
Open circuit in sensor wiring. Corroded or disconnected sensor connector. Failed sensor element (open resistance). ECM circuit failure (rare). Wiring damage from heat or chafing.
Sensor Location
On the Mazda3, the IAT sensor may be integrated into the mass airflow sensor or mounted separately in the intake tract. Location determines replacement approach.
Testing Procedure
Check sensor resistance—it should vary with temperature (typically 2-3k ohms at room temperature). Test connector for proper voltage and ground. Check wiring continuity from sensor to ECM.
Repair Costs
IAT sensor replacement costs $50-200 depending on integration with MAF. Wiring repair runs $100-250. If integrated with MAF sensor, replacement costs $150-400.