Diagnostic Aids
The Scan tester reads engine temperature in degrees centigrade. After engine is started, temperature should rise steadily to about 194°F (90°C), then stabilize when thermostat opens.
When a Code 15 is set, ECM will turn on engine cooling fan. Code 15 will set if circuits No. 410 or No. 452 are open. If Code 15 is intermittent, see INTERMITTENTS in TESTS W/O CODES article in this section.
COOLANT TEMPERATURE SENSOR RESISTANCE
| Temperature °C (°F) | Ohms |
|---|---|
| 100 (212) | 177 |
| 90 (194) | 241 |
| 80 (176) | 332 |
| 70 (158) | 467 |
| 60 (140) | 667 |
| 50 (122) | 973 |
| 45 (113) | 1188 |
| 40 (104) | 1459 |
| 35 (95) | 1802 |
| 30 (86) | 2238 |
| 25 (77) | 2796 |
| 20 (68) | 3520 |
| 15 (59) | 4450 |
| 10 (50) | 5670 |
| 5 (41) | 7280 |
| 0 (32) | 9420 |
| -5 (23) | 12300 |
| -10 (14) | 16180 |
| -15 (5) | 21450 |
| -20 (-4) | 28680 |
| -30 (-22) | 52700 |
| -40 (-40) | 100700 |