Intake Air Temperature Sensor 1/2 Correlation
The P2199 code indicates that the Engine Control Module (ECM) has detected a correlation error between the signals from Intake Air Temperature (IAT) Sensor 1 (usually located in the air intake duct) and IAT Sensor 2 (often integrated into the Mass Air Flow sensor or intake manifold). This mismatch suggests one sensor is reading significantly different from the other, which can affect air-fuel mixture calculations and engine performance.
01. Most Common Causes
- Faulty IAT sensor 1 or 2
- Wiring or connector issues (corrosion, damage, loose connections)
- Air intake system leaks (vacuum leaks, loose ducting)
- Contaminated or dirty IAT sensor
- ECM software or hardware problem (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Poor fuel economy
- Rough idle or hesitation during acceleration
- Black smoke from exhaust (rich mixture) or lack of power (lean mixture)
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm P2199 and check for other codes.
Step 2: Visually inspect IAT sensors and wiring for damage, corrosion, or loose connections.
Step 3: Compare live data from both IAT sensors with a scan tool; they should read similarly at ambient temperature.
Step 4: Test sensor resistance with a multimeter (specifications vary by vehicle; typically 2-5 kΩ at 68°F).
Step 5: Check for vacuum leaks or intake air restrictions that could affect sensor readings.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is generally safe for short trips, but prolonged driving can cause poor fuel economy, reduced performance, and potential damage to the catalytic converter due to incorrect air-fuel mixture.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for parts and labor, depending on whether a sensor needs replacement or just a wiring repair.