Temperature Sensors in Engine Management: NTC Curves, Calibration & Wiring
Temperature sensors are critical inputs in any electronic engine management system. From cold-start fuel enrichment to real-time air density calculations, your Engine Control Unit (ECU) relies on accurate temperature readings to optimize performance, fuel economy, and engine safety.
In this guide, we break down how automotive temperature sensors operate, why NTC thermistors require full calibration curves, how Coolant (CLT) and Intake Air (IAT) temperature readings differ, strategies to prevent heat soak, and how to wire them correctly into your harness.
Unlike linear 0–5V sensors (such as TPS or MAP sensors) that only require a 2-point linear calibration, automotive temperature sensors are non-linear NTC thermistors. They require a multi-point resistance-to-temperature calibration curve for accurate ECU calculations.