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.
1994 Geo Metro L3-61 1.0LFACTORY OEM SERVICE PROCEDURE
Coolant Temperature Sensor/Switch (For Computer)
ECT Sensor Temperature To Resistance Values:
ENGINE COOLANT TEMPERATURE SENSOR RESISTANCE VALUES
Refer to the chart in the accompanying image for sensor temperature to resistance values.
ECM PINOUT VOLTAGE VALUES
Voltage at Engine Control Module (ECM) pin A15 (LT GRN/BLK wire) varies according to engine coolant temperature:
Low Temperature: Approximately 5 volts
Normal Operating Temperature: 1.5 - 2 volts
High Temperature: Approximately 0.5 volt
Factory Service Tools
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.