P0099 - Intake Air Temperature Sensor 2 Circuit Intermittent/Erratic
Intake Air Temperature is monitored to allow the ECM to accurately adjust fueling and emission control systems as the temperature directly affects the air density
Fault Code Explained
The sensor output signal may be intermittently going in and out of it;s normal operating parameters or changing at a rate that is not consistent with the current engine operating conditions.
If possible use a diagnostic computer to view live data readings for the sensor and compare to actual air temperature. Test sensor supply Voltage and output signal