P00A9
Intake Air Temperature Sensor 2 Circuit Intermittent/Erratic Bank 2
Air intake / temperature sensing
Generic OBD-II
Low
What it means
P00A9 means the signal from the second intake air temperature sensor on bank 2 is cutting out or jumping around erratically. It's almost always a wiring or connector problem rather than the sensor itself. The engine keeps running, but the ECM loses accurate intake-air-temperature data during the dropouts, which can slightly affect fuel trims.
Low
Can I keep driving? Safe to drive — this is an intermittent sensor-signal fault; the engine keeps running normally, though fuel trims may occasionally be slightly off until it's fixed.
Common symptoms
What you'll notice
- Check-engine light on (often intermittently)
- Occasional slightly rough running or reduced fuel economy
- No symptoms noticeable much of the time
Common causes
Most likely first
- Loose, corroded, or backed-out connector at the IAT 2 sensor on bank 2Likely
- Chafed or intermittently shorted wiring in the sensor circuitCommon
- Faulty or dirty Intake Air Temperature sensor 2Common
- Poor ground or intermittent open in the harnessLess often
- ECM/PCM fault (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data, then wiggle-test the IAT 2 connector and harness while watching the live temperature reading for dropouts.
- Inspect the connector for corrosion, spread terminals, or moisture and reseat it.
- Check the wiring for chafing or intermittent shorts along its run on bank 2.
- Clean or replace the IAT 2 sensor if its signal is erratic.
- Clear the code and road-test to confirm the intermittent is gone.
FAQ
Quick answers
Is it safe to drive with P00A9?+
Yes. An intermittent intake-air-temperature signal has little effect on drivability; the ECM uses a default value when the reading drops out. Repair it to keep fuel trims accurate.
Can I just clear P00A9?+
You can, but because the fault is intermittent it will likely return. Find and fix the loose connection or wiring first.
Related codes
Often seen with P00A9
Read & clear P00A9 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX