P0099

Symptoms

• Check Engine light comes on
• Unstable engine idling
• Reduced engine power
• Increased fuel consumption
• Difficulty starting the engine
• Detonation during acceleration (for turbocharged engines)
• Black smoke from the exhaust pipe

Causes

• Intake air temperature sensor IAT2 malfunction
• Damaged or corroded sensor wiring
• Poor contact in the sensor connector
• Contamination or oxidation of connector contacts
• Open or short circuit in the sensor circuit
• Engine ECU malfunction
• Mechanical damage to the sensor
• Oil or dirt on the sensor

How to Fix

1. Connect the scanner and read the error codes
2. Check IAT2 sensor data in real time
3. Visually inspect the sensor and its wiring for damage
4. Check the condition of the sensor connector, clean the contacts
5. Measure the resistance of the sensor with a multimeter at different temperatures
6. Check the supply voltage and ground in the sensor connector
7. If necessary, replace the IAT2 sensor
8. Clear error codes and test drive
9. Recheck the system with a scanner

Related codes

Error P0099 by Vehicle Brand