Engine Coolant Temperature Sensor
- Manufacturer does not provide testing procedures for many individual systems and components. A malfunction in Engine Coolant Temperature (ECT) sensor circuit can set a DTC. For testing procedures and specifications, perform related DTC testing procedure. See SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL
article. An out-of-calibration ECT sensor may not set a DTC. Use the following procedure to test sensor calibration.
- Disconnect ECT sensor harness connector. Using DVOM, measure resistance of ECT sensor at specified temperatures. See TEMPERATURE VS. RESISTANCE table. Resistance should be high when engine is cold and drop as engine warms. With vehicle sitting overnight, IAT sensor and ECT sensor should have close to the same resistance reading. If resistance is not within specification, replace ECT sensor.
TEMPERATURE VS. RESISTANCE
| °F (°C) |
Ohms |
| 302 (150) |
47 |
| 284 (140) |
60 |
| 266 (130) |
77 |
| 248 (120) |
100 |
| 230 (110) |
132 |
| 212 (100) |
177 |
| 194 (90) |
241 |
| 176 (80) |
332 |
| 158 (70) |
467 |
| 140 (60) |
667 |
| 122 (50) |
973 |
| 113 (45) |
1188 |
| 104 (40) |
1459 |
| 95 (35) |
1802 |
| 86 (30) |
2238 |
| 77 (25) |
2796 |
| 68 (20) |
3520 |
| 59 (15) |
4450 |
| 50 (10) |
5670 |
| 41 (5) |
7280 |
| 32 (0) |
9420 |
| 23 (-5) |
12,300 |
| 14 (-10) |
16,180 |
| 5 (-15) |
21,450 |
| -4 (-20) |
28,680 |
| -22 (-30) |
52,700 |
| -40 (-40) |
100,700 |