Diagnostic Procedures
- Perform On-Board Diagnostic II (OBD-II) system check. See
SELF-DIAGNOSTICS - INTRODUCTION article. Go to next step.
- Turn ignition on. Using scan tool, read Intake Air Temperature (IAT) value. If temperature is more than 283°F (148°C), go to step 4. If temperature is 283°F (148°C) or less, go to next step.
- Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read specified DTC. If scan tool displays DTC P0112 FAILED THIS IGN, test IAT sensor. Using a DVOM, measure resistance across IAT sensor terminals. See IAT SENSOR RESISTANCE table. Replace IAT sensor if resistance is not as specified. If scan tool does not display DTC P0112 FAILED THIS IGN, go to DIAGNOSTIC AIDS .
IAT SENSOR RESISTANCE
| Temperature °F (°C) |
Ohms |
| 212° (100°) |
177 |
| 176° (80°) |
332 |
| 140° (60°) |
667 |
| 113° (45°) |
1188 |
| 95° (35°) |
1802 |
| 77° (25°) |
2796 |
| 59° (15°) |
4450 |
| 41° (5°) |
7280 |
| 23° (-5°) |
12,300 |
| 5° (-15°) |
21,450 |
| -22° (-30°) |
52700 |
| -40° (-40°) |
100700 |
- Turn ignition off. Disconnect IAT sensor harness connector. Turn ignition on. Using scan tool, read IAT value. If reading is less than -36°F (-38°C), go to step 6. If reading is -36°F (-38°C) or more, go to next step.
- Turn ignition off. Disconnect PCM connectors. Check IAT sensor input circuit for short to ground (Yellow/Green wire). Repair as necessary. If no problem was found, go to step 7.
- Replace IAT sensor. Retest system.
- Replace and reprogram PCM using required equipment. See PROGRAMMING . Retest system.