Intake Air Temperature Sensor 2 Circuit Intermittent/Erratic Bank 1
The P0099 code indicates that the Powertrain Control Module (PCM) has detected an intermittent or erratic signal from the Intake Air Temperature (IAT) sensor 2 on bank 1. This sensor monitors the temperature of the air entering the engine, and an erratic reading can cause incorrect air-fuel mixture calculations, leading to performance issues. The problem is often due to a faulty sensor, damaged wiring, or poor electrical connections.
01. Most Common Causes
- Faulty Intake Air Temperature Sensor 2
- Damaged or corroded wiring/connectors
- Intermittent short or open in the sensor circuit
- Poor electrical connection at the sensor or PCM
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Rough idle or hesitation during acceleration
- Decreased fuel economy
- Black smoke from exhaust (rich mixture)
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for additional codes.
Step 2: Visually inspect the IAT sensor 2 and its wiring for damage, corrosion, or loose connections.
Step 3: Test the sensor's resistance with a multimeter and compare to manufacturer specifications.
Step 4: Check the voltage signal at the PCM connector to ensure proper communication.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as the erratic sensor reading can cause poor engine performance and potential damage to the catalytic converter.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for parts and labor, depending on the vehicle and shop rates.