- Check Ground Circuit Turn ignition off. Disconnect ECT harness connector. (Scheme 6) Using an ohmmeter, check continuity between ECT harness connect or terminal No. 1 (Black wire) and engine ground. If no continuity exists, repair open in Black wire. If continuity exists, go to next step.
- Check Power Supply Turn ignition on. Using a voltmeter, measure voltage between ECT sensor harness connector terminal No. 2 (Yellow wire) and ground. If voltage is not approximately 5 volts, repair fault in Yellow wire as required. If measured voltage is approximately 5 volts, go to next step.
- Check Component Leave sensor disconnected. Measure resistance across sensor connector terminals. See ENGINE COOLANT TEMPERATURE (ECT) SENSOR RESISTANCE table. If resistance is not as specified, replace sensor. If resistance is as specified, check thermostat for correct operation. If thermostat operation is okay, check ECM connector for damage or corrosion. Disconnect and reconnect harness connectors in circuit and perform «FINAL CHECK»(ref-17943-S12355810372001121700000), see appropriate section in this article.
| Temperature °F (°C) | Ohms |
|---|---|
| 68 (20) | 2100-2900 |
| 122 (50) | 680-1000 |
| 194 (90) | 236-260 |
ENGINE (COOLANT) TEMPERATURE SENSOR RESISTANCE
