Diagnostic Aids
Tech 1 displays engine temperature in degrees Celsius (°C). After engine is started, temperature should rise steadily to about 90°C, then stabilize when thermostat opens. An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside insulation. Check the following for:
- A short to ground in coolant sensor signal circuit.
- Intermittent Test
Using scan tester, monitor engine coolant temperature while moving related connectors and wiring harness. If failure is induced, display will change. This may assist in isolating location of malfunction.
- Shifted Sensor
See TEMPERATURE-TO-RESISTANCE VALUES table to test ECT sensor at various temperature levels to evaluate possibility of a shifted (mis-scaled) sensor which may result in driveability complaints.
TEMPERATURE-TO-RESISTANCE VALUES (1)
| Temperature °F (°C) | Ohms | ||
|---|---|---|---|
| 212 (100) | 177 | ||
| 194 (90) | 241 | ||
| 158 (70) | 467 | ||
| 104 (40) | 1459 | ||
| 68 (20) | 3520 | ||
| 23 (-5) | 12,300 | ||
| 14 (-10) | 16,180 | ||
| 0 (-18) | 25,000 | ||
| -4 (-20) | 28,680 | ||
| -22 (-30) | 52,700 | ||
| -40 (-40) | 100,700 | ||
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