Applicable Systems
OBD-II
Symptoms
IAT sensor signal indicates temperature above maximum (short circuit); ECM may run very rich.
Possible Causes
- IAT sensor signal wire short to ground
- IAT sensor internal short
- Connector water intrusion
Troubleshooting Steps
- Step 1: Check IAT sensor signal wire for short to ground
No short to ground - Step 2: Inspect connector for moisture
Connector dry - Step 3: Measure sensor resistance (should be 200-300 ohm at 25C)
Resistance within range - Step 4: Replace IAT sensor if resistance too low
New sensor resistance normal - Step 5: Clear code and verify reading
IAT reads ambient temp
How to Reset
Clear with OBD-II scanner after repair.
Common Replacement Parts
- IAT Sensor (OEM spec)
Frequently Asked Questions
- Q: What temperature does P0112 indicate?
Signal corresponds to temperature above 140C, which is impossible for intake air. Indicates sensor or wiring fault.
Source: SAE J2012 standard DTC list + OBD-II portal
Category: OBD-II