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 for:
- Poor Connection Or Damaged Harness
Inspect PCM harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection, and damaged harness.
- 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.
- A faulty connection, or an open in sensor circuits will cause Code P0117 to set.
| 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 | ||
|
|||