Q: How to check and replace the Engine Coolant Temperature (ECT) sensor?
A: The Engine Coolant Temperature (ECT) sensor, a thermistor, adjusts its resistance with temperature changes. It's in the intake manifold on SOHC engines and the engine's back on DOHC. Faults yield error codes. To test, remove the sensor, immerse it in heated water, and measure resistance. Match readings to a temperature-resistance chart. If off, replace the ECT. For replacement, disconnect it, use Teflon tape on the new sensor's threads, install, tighten to the right torque, and refill coolant if needed.