ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION[LF, L3]

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Resistance Inspection

Note
•  Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart.

1.  Disconnect the ECT sensor connector.

2.  Remove the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION[LF, L3].)

3.  Place the ECT sensor in the water and while increasing the water temperature, measure the resistance between ECT sensor terminals A and B.

•  If the monitor item status/specification (reference) is not within the specification, even though the ECT sensor resistance is within the specification, perform the “Circuit Open/Short Inspection”.
•  If not within the specification, replace the ECT sensor.

Standard

Water temperature

(°C {°F})

Resistance (kilohm)
20 {68}
35.48—39.20
70 {158}
5.07—5.60
80 {176}
3.65—4.02


Circuit Open/Short Inspection

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1.  Disconnect the PCM connector. (See PCM REMOVAL/INSTALLATION[LF, L3].)

2.  Inspect the following wiring harnesses for open or short. (Continuity check)


Open circuit

•  If there is no continuity, the circuit is open. Repair or replace the harness.
―  ECT sensor terminal A and PCM terminal 2AH*1, 2AK*2
―  ECT sensor terminal B and PCM terminal 2P*1, 2AA*2


Short circuit

•  If there is continuity, the circuit is shorted. Repair or replace the harness.
―  ECT sensor terminal A and power supply
―  ECT sensor terminal A and body ground
―  ECT sensor terminal B and power supply

*1  :MTX, LF ATX (FS5A-EL)
*2  :LF ATX(FN4A-EL), L3 ATX