P0099 code meaning
Intake Air Temperature Sensor 2 Circuit Intermittent/Erratic Bank 1
Powertrain system Generic code P00xx codes Check engine light
What P0099 means
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.
P0099 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 2 hours
- Clears after repairAfter a drive cycle
Symptoms of P0099
- Check engine light on
- Usually no noticeable symptoms
- Emissions test or readiness check may fail
Common causes of P0099
- Most likelyLoose contact or wire broken by movement
- PossibleSensor failing intermittently
- Less likelyInterference on the signal wire
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Intake air temperature sensor 2Intake air temperature sensor wiringManifold absolute pressure sensor
What each part of P0099 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 0 | Area: fuel and air metering and auxiliary emission controls. |
| 99 | The exact fault in that area. |
What to do next
- Note P0099 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0099
What does P0099 mean?
P0099 means "Intake Air Temperature Sensor 2 Circuit Intermittent/Erratic Bank 1". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P0099?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P0099 fail an emissions test?
Yes, it can. P0099 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0099 to fix?
Difficulty: easy. A typical repair takes 0.3 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0099 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.