P0098: Intake Air Temperature Sensor 2 Circuit High
The intake air temperature sensor 2 signal is above its normal range.
Normal risk
Usually safe to drive. Have it checked at the next opportunity.
Short answer · Can I keep driving with P0098?
Yes, usually. The engine uses a default value instead, so economy and power may suffer slightly. Have it checked at the next opportunity.
What does P0098 mean?
Code P0098 means that the signal of intake air temperature sensor 2 is higher than a working sensor gives, which the control unit reads as a very low temperature. An open circuit, a disconnected plug or a failed sensor are typical causes. On many engines sensor 2 sits after the turbocharger and intercooler or in the intake manifold, so it measures the air that actually enters the engine.
What the car does when the code is set
The check engine light comes on and the engine uses a fixed substitute temperature. Most drivers notice no difference. Some cars start less easily in very cold or very hot weather or use slightly more fuel.
How the system works
The intake air temperature sensor is a thermistor whose resistance falls as the air gets warmer. The engine control unit feeds it a reference voltage of about 5 volts and reads how much is left: a high voltage means cold air, a low voltage warm air. The reading is used to correct fuel quantity and ignition timing, because cold air is denser than warm air. If the signal is stuck at either end of its range, the control unit recognises a circuit fault and replaces the reading with a fixed value.
Common symptoms
Possible causes
Listed without ranking. The cause on your car depends on make, engine and mileage — see the maker notes below.
- Open circuit or unplugged sensorA broken wire or loose connector makes the reading jump to its coldest value.
- Corroded connectorCorrosion adds resistance to the circuit.
- Faulty sensorThe sensor resistance no longer changes correctly with temperature.
- Wiring damageChafed wires near the intake or engine.
How it is diagnosed
- Compare with outside temperatureWith a cold engine, the intake air temperature should be close to the outside temperature. A reading of about −40 °C usually means an open circuit.
- Check the connectorUnplug the sensor (it is often part of the air-flow sensor) and look for corrosion and bent pins.
- Measure resistance and voltageCompare the sensor resistance at a known temperature and the reference voltage with the service data.
- Repair and clearAfter a repair, clear the code and check that the reading follows the real temperature.
Questions about P0098
Where is intake air temperature sensor 2?
It depends on the engine: often in the charge air pipe after the intercooler or in the intake manifold, sometimes combined with the boost pressure sensor. The service data shows its position.
Will this code affect fuel economy?
Slightly. The engine uses a substitute temperature, so the mixture is less precisely matched to the real air density.
Is the sensor part of the air-flow sensor?
On many cars it is, so the whole air-flow sensor is replaced. On others it sits separately in the intake duct or manifold.