Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Description & Operation: Description
Water temperature sensor (WTS) is located in the engine coolant passage of the cylinder head for detecting the engine coolant temperature.
The WTS uses a thermistor whose resistance changes with the temperature.
The electrical resistance of the WTS decreases as the temperature increases, and increases as the temperature decreases.
The reference +5V is supplied to the WTS via a resistor in the ECM. That is, the resistor in the ECM and the thermistor in the WTS are connected in series.
When the resistance value of the thermistor in the WTS changes according to the engine coolant temperature, the output voltage also changes.
During cold engine operation, the ECM increases the fuel injection duration and controls the ignition timing using the information of engine coolant temperature to avoid engine stalling and improve drivability.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.