Intake Air Temperature Sensor 1/2 Correlation
P2199 indicates that the signals from the two intake air temperature (IAT) sensors (typically one in the air intake duct and one in the intake manifold) are not correlating within a specified range. This can be caused by a faulty sensor, wiring issues, or a restriction in the intake system. The PCM uses these sensors to adjust fuel delivery and ignition timing; a mismatch can lead to poor engine performance.
1. Most Common Causes
- Faulty IAT sensor 1 or IAT sensor 2
- Actual temperature difference due to an obstruction or restriction in the intake duct
- Corroded, damaged, or high-resistance wiring or connectors in either sensor circuit
- Unmetered air leak (vacuum or boost) affecting only one measurement zone
- Internal ECM/PCM failure (less common)
- Dirt or contamination buildup on one of the sensors
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Rough idle or hesitation
- Poor fuel economy
- Possible hard starting
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect IAT sensors and wiring for damage or corrosion.
Step 3: Compare IAT sensor readings with a scan tool; they should be similar at key-on engine-off.
Step 4: Test sensor resistance and voltage according to manufacturer specs.
Step 5: Check for intake air leaks or restrictions.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is generally safe for short distances, but may cause poor performance and reduced fuel economy. Prolonged driving could lead to catalytic converter damage.
How much does it cost to fix?▼
Typically $50-$150 for parts and labor, depending on the sensor location and labor rates.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.