Diagnostic Procedures
- Perform OBD-II system check. See ON-BOARD DIAGNOSTIC II (OBD-II) SYSTEM CHECK
. After performing OBD-II system check, 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, monitor specified DTC parameters. 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°) |
52,700 |
| -40° (-40°) |
100,700 |
- 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 harness connectors. Check for short to ground in Yellow/Green wire between PCM harness connector terminal B8 and IAT sensor. See Figure
and Fig 1
. 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.
Courtesy of ISUZU MOTOR CO.