What Does P1116 Mean?
P1116 indicates the Intake Air Temperature (IAT) sensor circuit is intermittently producing a higher-than-expected voltage. This means the ECM periodically reads an unrealistically cold air temperature, causing it to add extra fuel enrichment and potentially retard ignition timing. The intermittent nature suggests a loose connection or degraded sensor rather than a complete circuit failure.
Common Causes
30%
IAT sensor connector loose or corroded causing intermittent open circuit
25%
IAT sensor developing intermittent high internal resistance
20%
Broken wire in the IAT signal or ground circuit
15%
Air filter housing not properly sealed, exposing connector to moisture
10%
ECM connector issue at the IAT signal pin
Diagnostic Steps
1
Step 1: Monitor IAT sensor live data. Normal readings should correspond to ambient or under-hood temperature (80–200°F depending on conditions). Intermittent readings of -40°F indicate the circuit is going open.
2
Step 2: Locate the IAT sensor — typically integrated into the MAF sensor housing or in the intake duct after the air filter. Inspect the connector for corrosion, bent pins, or loose fit.
3
Step 3: Wiggle the IAT connector and wiring while monitoring live data. Voltage spikes or temperature reading drops during the test pinpoint the fault location.
4
Step 4: Disconnect the IAT sensor and measure resistance. At 70°F, expect approximately 2,000–3,000 ohms. At 200°F, expect approximately 200–400 ohms. Infinite or erratic resistance confirms sensor failure.
5
Step 5: If the sensor is integrated into the MAF housing, the entire MAF assembly may need replacement. Otherwise, replace the standalone IAT sensor and clear codes.
Estimated Repair Cost
$25 - $200
Parts + labor, varies by vehicle and location
P1116 indicates the Intake Air Temperature (IAT) sensor circuit is intermittently producing a higher-than-expected voltage. This means the ECM periodically reads an unrealistically cold air temperature, causing it to add extra fuel enrichment and potentially retard ignition timing. The intermittent ...
The most common cause of P1116 (Intake Air Temperature (IAT) Sensor Circuit Intermittent High Voltage) is: IAT sensor connector loose or corroded causing intermittent open circuit
Typical repair costs for P1116 range from $25 to $200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Intermittent high IAT voltage causes momentary over-fueling, resulting in poor fuel economy and slightly elevated emissions. No significant safety hazard, but sustained rich running can damage the catalytic converter over time.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1116 to identify the root cause.
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Quick Info
Category
Powertrain
System
Engine Management / Air Metering
Difficulty
Type
Manufacturer
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