P0098–P00AD Intake Air Temperature Sensor 2 Circuit High Bank 1

Which code is which

Same fault, different cylinder or bank — diagnosed the same way. Several set together usually means one shared cause.

The definition

P0098: Intake Air Temperature Sensor 2 Circuit High Bank 1.

P0098 is a powertrain code (the engine or gearbox), defined by the SAE standard - it means the same thing on any make of car, and any generic OBD-II reader will decode it.

What to check first

Cheapest and fastest checks first:

1. Unplug the sensor and check whether the signal falls. If it stays high, suspect the wiring rather than the sensor.
2. Check the earth path - a missing earth makes a sensor read high.

What actually causes this on a VAG

Intake air temperature sensor 2 is the one measuring the air after it has been through the turbocharger and intercooler, rather than the cool air entering the airbox. On many VAG turbo engines it is not a separate part at all but built into the charge pressure sensor in the intake manifold or charge pipe. "Circuit High" means the ECU is seeing an unusually high voltage on the signal wire, which for this type of sensor reads as an impossibly cold temperature - the classic signature of a broken or disconnected circuit. The car can feel flat, because the ECU falls back to a safe substitute value and may rein the boost in, though on plenty of cars the only sign is the warning light.

Most likely causes, in order

1. Unplugged, broken or chafed wiring at the sensor. Very common after any work involving the intercooler, charge pipes, turbo or manifold - the plug gets left off or the retaining clip breaks. Confirm it in live data: if the reading is pinned at the coldest value the ECU can display while the engine is hot, the circuit is open rather than reading badly. Wiggle the loom with the reading on screen.
2. The sensor, or the combined pressure-and-temperature sensor, has failed. These fail internally and the combined charge-pressure-and-temperature sensor is a known failure point on VAG turbo engines. Before ordering, be sure which sensor you actually need - because the temperature element is often inside the boost pressure sensor, owners frequently buy the airbox or intake air temperature sensor by mistake and fit a perfectly good part to the wrong place.
3. A lost earth or reference supply on the sensor circuit. If the sensor's earth or supply wire is broken or corroded, the signal line sits high and the ECU reports exactly this. Check whether other sensors have logged faults at the same time - several unrelated codes together point at a shared wiring or earth problem rather than one failed sensor.

Worth knowing: Trust the live data over the code text. A charge-air temperature that stays at its minimum displayed value with a hot engine is an open circuit, and no new sensor will fix a broken wire or an unplugged connector. Check the plug first - on these engines it is very often simply not connected after previous work.

Common questions

What does P0098 mean?

P0098 means Intake Air Temperature Sensor 2 Circuit High Bank 1. The voltage on this circuit is sitting near battery voltage. Typically a short to a positive feed, or a disconnected sensor floating high.

Can I drive with P0098?

The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.

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