Disconnect suspect temperature sensor. Set DVOM to 200 k/ohm scale. Measure resistance between sensor terminals. Refer to ECT & ACT TEMPERATURE SENSORS VOLTAGE & RESISTANCE SPECIFICATIONS (EXCEPT PROBE 2.2L) table for voltage and resistance specifications for all models except Probe with 2.2L. Refer to ECT & VAT TEMPERATURE SENSORS VOLTAGE & RESISTANCE SPECIFICATIONS (PROBE 2.2L) table for voltage and resistance specifications for Probe models with 2.2L. See Fig 1 .

ECT & ACT TEMP SENSORS VOLTAGE & RESISTANCE SPECS (EXCEPT PROBE 2.2L)

ECT & VAT TEMP SENSORS VOLTAGE & RESISTANCE SPECS (PROBE 2.2L)

Temperature °F (°C)

Voltage

⁽¹⁾ Resistance Ohms

-4 (-20)

4.70

10-20

32 (0)

3.40

4-7

68 (20)

2.50

2-3

104 (40)

2.00

0.9-1.3

140 (60)

1.20

0.4-0.7

176 (80)

0.70

0.2-0.4

⁽¹⁾	Measure resistance between sensor signal circuit and SIG RTN pin.

Fig 1: Temperature Sensor Voltage & Resistance Graph

Courtesy of FORD MOTOR CO.

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.

Safety Warning

Engine Coolant Temperature (ECT) Sensor Test