P0112 means Intake Air Temperature Sensor Circuit Low. The intake air temperature signal voltage is too low, which the computer reads as an impossibly hot intake temperature. It is a generic OBD-II code, so the definition is the same on any make, but the most likely cause varies by engine; confirm with a scan tool and the service information for your vehicle before buying parts.
What P0112 means
Most engine sensors receive a 5-volt reference and return a signal between roughly 0 and 5 volts. Codes ending in circuit high or circuit low usually point to an electrical fault: an open circuit, a short or an unplugged connector. Range/performance codes mean a signal is present but disagrees with what the computer expects from the other sensors, which more often points to a dirty sensor, an air leak or a mechanical problem.
P0112 symptoms
- Check engine light
- Possible hard cold starts or hesitation
- Poor fuel economy on some vehicles
Common causes of P0112
- Shorted wiring to ground
- Failed sensor
- Damaged connector
How to diagnose P0112
- Look for an IAT reading far hotter than the engine could be
- Unplug the sensor: the reading should swing very cold if the wiring is good
- Inspect the harness for chafing
Can you drive with P0112?
Usually yes.
P0112 tips
The IAT sensor reads hot when its signal is shorted to ground. Unplugging the connector should make the reading drop to very cold; if it does not, the short is in the wiring.
Will P0112 clear itself?
If the fault stops, the computer turns off the check engine light by itself after several drive cycles without seeing it again, and the code stays in memory as history for a while. Clearing P0112 with a scan tool after a repair is fine, but if the cause is still there the code returns, sometimes within one drive. Disconnecting the battery also clears codes on most vehicles, but it erases learned fuel trims and idle settings as well.
Related codes
| Code | Meaning |
|---|---|
| P0113 | Intake Air Temperature Sensor 1 Circuit High |
| P0110 | Intake Air Temperature Sensor Circuit |
| P0101 | Mass or Volume Air Flow Circuit Range/Performance |
Guides that help
When it is more than a sensor
Sensor codes are usually fixed with a sensor, a connector, wiring or a leak repair rather than major parts. If testing turns up internal engine trouble instead, see how to tell if an engine is blown and compare engines by code on our engines page.
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