Pinpoint Test ECT - Engine Coolant Temperature Sensor
NOTE:
Enter this test only when a Code 09 is displayed during QUICK TESTS procedure or when directed here from another PINPOINT TEST. To prevent unnecessary diagnosis, inspect coolant level, oil level, cooling fan, thermostat, and airflow to radiator before testing.
ECT CIRCUIT PIN IDENTIFICATION
| Circuit | PCM Pin | BOB Pin | Wire Color |
|---|---|---|---|
| ECT | 2H | 51 | RED/BLU |
| SIGRTN | 2D | 46 | YEL/GRN |
1) Start and run engine until coolant temperature reaches 176°F (80°C). Turn ignition off. Install BOB. Leave PCM disconnected. Measure resistance between BOB test pins 51 and 46. If resistance is not 250-350 ohms, go to next step. If resistance is as specified, ECT circuit is okay.
2) Unplug ECT sensor, threaded into intake manifold. Inspect ECT wire (Red/Blue) between ECT and PCM for shorts or opens. If wire is okay, go to next step. Repair ECT wire as necessary.
3) Inspect SIGRTN wire (Yellow/Green) between ECT and PCM for opens. Repair SIGRTN wire as necessary. If wire is okay, replace ECT sensor.