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.
Engine Coolant Temperature Sensor
The Engine Coolant Temperature (ECT) Sensor provides an input voltage to the ECM relating to coolant temperature. The ECM uses this input signal along with inputs from other sensors to determine injector pulse width and ignition timing. As coolant temperature varies the ECT Sensor's resistance changes. The change in resistance results in a different input voltage to the ECM. When the engine is cold, the ECM will operate in Open Loop cycle. It will demand slightly richer air/fuel mixtures and higher idle speeds until normal temperatures are reached.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.
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