P0098
Intake Air Temperature Sensor 2 Circuit High Bank 1P0098 is a generic OBD-II powertrain diagnostic trouble code: Intake Air Temperature Sensor 2 Circuit High Bank 1. It is logged by the engine control unit when the powertrain monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What P0098 means
P0098 is set when the ECM detects a voltage on the Intake Air Temperature Sensor 2 (IAT2) signal circuit that is above the sensor's maximum acceptable threshold — typically above approximately 4.8–4.9 V. Because IAT2 is an NTC thermistor (resistance decreases with rising temperature), a high signal voltage normally indicates very cold air. When the voltage exceeds the physical maximum the sensor can produce, the ECM concludes the circuit has an open fault or is shorted to the 5 V reference supply rather than reflecting a real temperature.
The most frequent cause of a stuck-high signal is a fully disconnected sensor, an open circuit in the signal or ground wire, or a short of the signal wire to the 5 V reference line. With the signal wire open or pulled to 5 V, the ECM reads an apparent temperature well below -40 °C, which is outside the sensor's calibrated range. The ECM flags P0098 and substitutes a fixed temperature value for fuelling and ignition calculations, potentially affecting charge-density corrections on turbocharged engines.
IAT2 is typically fitted post-intercooler on forced-induction petrol and diesel engines (VW/Audi 2.0T, Ford EcoBoost, GM LTG). A frozen-low substitute temperature can lead to lean fuelling corrections and, on high-boost engines, an increase in knock risk, since the ECM underestimates actual charge air temperature and may not apply sufficient enrichment or timing retard under load.
Common causes
Most-frequently reported root causes when P0098 is logged.
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1
IAT2 sensor connector fully disconnected, leaving the signal line floating at the ECM pull-up voltage.
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2
Open circuit in the IAT2 signal wire between the sensor and ECM.
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3
Open circuit in the IAT2 sensor ground wire preventing the thermistor voltage divider from functioning.
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4
Short circuit of the IAT2 signal wire to the 5 V reference supply wire in the harness.
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5
Internal open circuit within the IAT2 sensor element itself.
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6
Corroded or physically broken connector pins causing loss of continuity on the signal or ground line.
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7
Damaged wiring insulation allowing the signal wire to contact the reference supply line inside a common conduit.
Symptoms drivers notice
How to diagnose P0098
A typical diagnostic flow when this code is present.
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1
Connect a scan tool, read live IAT2 data — a reading near or below -40 °C with the engine at any temperature strongly suggests a circuit-high (open or short-to-reference) fault.
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2
Physically inspect the IAT2 sensor connector: confirm it is fully seated and check for bent, corroded, or pushed-out pins.
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3
With the sensor connected and ignition on (engine off), backprobe the signal wire; a reading near 5 V confirms the circuit is open or shorted to reference.
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4
Disconnect the sensor connector: if signal voltage drops from ~5 V to near 0 V, the open or pull-up issue is inside the sensor (replace the sensor); if it stays near 5 V, the harness signal wire is shorted to the reference supply.
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5
Check continuity of the sensor ground wire from the connector pin to chassis/ECM ground; any open reading must be repaired.
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6
Repair or replace the confirmed faulty component, clear codes, and confirm IAT2 tracks realistically from cold to operating temperature during a test drive.
Related powertrain codes
Frequently asked questions
Is a disconnected IAT2 sensor the most common cause of P0098?
Yes. When the connector is disconnected, the ECM's internal pull-up resistor drives the signal line to approximately 5 V, which the ECM interprets as a temperature below -40 °C — outside the sensor range. This is why P0098 (circuit high) is almost always the first code you see when a sensor is simply unplugged.
Can P0098 damage the engine?
Indirectly. On turbocharged engines, if the ECM substitutes a very cold temperature value it may under-enrich the mixture or fail to retard ignition during periods of genuinely hot charge air. On aggressive tunes or high-boost setups this could increase knock risk. Under factory calibration the risk is low but the code should still be repaired.
How does P0098 differ from P0097?
P0097 is a circuit-low fault — signal voltage is stuck near 0 V, typically from a short to ground or internal sensor short, and reads as an extremely high temperature. P0098 is a circuit-high fault — signal voltage is stuck near 5 V, typically from an open circuit or short to reference, and reads as an extremely low temperature.
Which vehicles commonly set P0098?
Any turbocharged or supercharged vehicle equipped with a second IAT sensor downstream of the intercooler is susceptible. Common examples include VW/Audi 2.0 TSI and TDI engines, Ford EcoBoost 1.5T and 2.0T, and GM LTG 2.0T (Chevrolet Camaro, Cadillac ATS). Normally-aspirated vehicles with a single IAT sensor will not set this code.
Disabling P0098 in software
RaceTune can permanently disable P0098 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
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