Diagnostic Aids
Ensure TFT, IAT and ECT connectors are clean and tight. With ignition on and engine cold, check TFT versus ECT versus IAT sensor temperatures. Compare sensor readings. Readings should similar. See TEMPERATURE SENSOR SPECIFICATIONS table.
If temperature is different than actual temperature reading, inspect continuity of circuits between each sensor and PCM. Repair as needed. If continuity of circuits are okay, test sensors with engine at normal operating temperature. Replace sensor(s) as needed.
TEMPERATURE SENSOR SPECIFICATIONS
| Temperature °F (°C) | ohms |
|---|---|
| -40 (-40) | 77000-109000 |
| -20 (-29) | 39000-53000 |
| 0 (-18) | 21000-27000 |
| 20 (-7) | 11000-15000 |
| 40 (4) | 6600-8400 |
| 60 (16) | 3900-4500 |
| 80 (27) | 2400-2700 |
| 100 (38) | 1500-1700 |
| 120 (49) | 980-1100 |
| 140 (60) | 650-730 |
| 160 (72) | 430-480 |
| 180 (83) | 302-334 |
| 200 (94) | 215-235 |
| 220 (105) | 159-172 |
| 248 (120) | 104-113 |
| 284 (140) | 63-68 |