Technician A says that changes in road surfaces can cause oscillations in the data log. Technician B says that the IAT data should always match the ECT data. Which technician is correct?

Technician A says that changes in road surfaces can cause oscillations in the data log. Technician B says that the IAT data should always match the ECT data. Which technician is correct?

• A. Neither
• B. Tech A
• C. Tech B
• D. Both

Answer: (B)

The main idea is how temperature sensor readings relate to each other in a running engine. In a properly functioning system, the intake air temperature (IAT) and the engine coolant temperature (ECT) should move together in a predictable way as the engine warms up and reaches thermal equilibrium. If the engine is cold, both stay low; as it warms, both readings rise and follow a similar trend. Large, unexplained differences between IAT and ECT indicate something is off with one of the sensors or the data log. Technician B is correct because, in normal operation, IAT and ECT should track each other closely in a way that reflects the engine’s thermal state. If road-surface changes were the primary cause of oscillations in the data log, that would be a less reliable and less consistent explanation for why these two temperature readings should correlate. Road conditions can affect dynamic load, but the expected relationship between IAT and ECT comes from how the engine and intake tract heat up together, not from road texture. So the correct idea is that the IAT data should generally match in trend with the ECT data, indicating proper thermal behavior and sensor function.

The main idea is how temperature sensor readings relate to each other in a running engine. In a properly functioning system, the intake air temperature (IAT) and the engine coolant temperature (ECT) should move together in a predictable way as the engine warms up and reaches thermal equilibrium. If the engine is cold, both stay low; as it warms, both readings rise and follow a similar trend. Large, unexplained differences between IAT and ECT indicate something is off with one of the sensors or the data log.

Technician B is correct because, in normal operation, IAT and ECT should track each other closely in a way that reflects the engine’s thermal state. If road-surface changes were the primary cause of oscillations in the data log, that would be a less reliable and less consistent explanation for why these two temperature readings should correlate. Road conditions can affect dynamic load, but the expected relationship between IAT and ECT comes from how the engine and intake tract heat up together, not from road texture.

So the correct idea is that the IAT data should generally match in trend with the ECT data, indicating proper thermal behavior and sensor function.