P0099: Intake Air Temperature Sensor 2 Circuit Intermittent/Erratic Bank 1

What does P0099 mean?

Intake air temperature sensor 2 is the second air temperature sensor in the intake path; on many turbocharged engines it sits in the intake manifold, often combined with the manifold pressure sensor, and is used to calculate cylinder filling and ignition timing. For P0099, the signal jumps faster than a real temperature can change, which typically points to a loose contact.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine light on
• Usually no noticeable symptoms
• Emissions test or readiness check may fail

Common causes

• High Loose contact or wire broken by movement
• Medium Sensor failing intermittently
• Low Interference on the signal wire

Likelihood is a general estimate across vehicles; your make and model may differ.