The OBD2 code P0098 is indicative of a “Intake Air Temperature (IAT) Sensor 2 Circuit High Input” situation within a vehicle. This diagnostic trouble code surfaces when the engine control module (ECM) detects that the input voltage from the second IAT sensor is higher than expected.
It’s a signal that the sensor might not be accurately measuring the air’s temperature entering the engine, which can impact the engine’s performance by altering the fuel-air mixture incorrectly.
P0098 quick overview
| Meaning | P0098: Intake Air Temperature (IAT) Sensor 2 Circuit High Input |
| Is it serious? | Yes, because it can affect engine efficiency and performance, though immediate symptoms might not always be noticeable. |
| Possible causes | – Faulty IAT sensor – Short to power in the IAT sensor circuit – Poor electrical connection in the IAT sensor circuit |
| How to diagnose? | Inspect the IAT sensor and its wiring for signs of damage or corrosion. Check the IAT sensor connector for proper connection and signs of damage. Test the IAT sensor circuit for continuity and voltage drop. Inspect the intake air system for leaks or obstructions. Consider replacing the IAT sensor if diagnostics indicate it’s faulty. |
P0098 Meaning
Imagine your car has a little thermometer (the IAT sensor) that tells it how warm or cold the air is as it comes into the engine. This helps your car decide how much fuel to mix with that air for the engine to run right. When the P0098 code pops up, it means this thermometer is sending a signal that’s too “hot” to the car’s computer, even if that’s not really the case.
This can make the engine run less efficiently because the computer might think it’s getting warmer air than it actually is. Fixing this issue helps ensure your car mixes fuel and air correctly for smooth operation.
Car Diagnostics Training
- Car Electrical basics
- OBD-II scanner basics
- How to use an OBD reader
- Introduction to a Bi-directional Scan tool
- OBD scanner buyer’s guide + discounts
How to fix P0098 – learn from mechanics
I looked into P0098 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.
Case #1: Chevrolet P0098
Vehicle Information 2009 Chevrolet C5500 Kodiak C5E042 6.6L
Issue + Repair History
- Codes P0299 (Turbocharger underboost) and P0098 (Intake air temp sensor 2 circuit high).
- Replaced intake air temp sensor 2 due to carbon buildup.
- MAP sensor and MAF sensor previously replaced.
- Oil and carbon buildup found in the intake system.
- Oil present in the intercooler and intake pipes from the turbocharger.
Other OBD2 Codes + Test Results
- OBD2 Codes: P0299 (Turbocharger underboost) and P0098 (Intake air temp sensor 2 circuit high).
- Live data shows high intake air temperature readings.
- MAP sensor found plugged with oil and carbon buildup.
Mechanic Suggestions
- Consider installing an intake manifold inlet upgrade to relocate the MAP sensor away from oil swirl.
- Drain or clean out any oil buildup in the CAC (Charge Air Cooler).
- Remove upper intake pipe and EGR to clean out sludge buildup in the intake.
- Pressure wash intake components with soap and hot water, then rinse and dry thoroughly.
- Inspect the turbocharger unison ring for sticking or wear and replace if necessary.
- Clean or replace the EGR cooler and valve while performing other maintenance.
Final Fix After contacting the dealer, it was determined that an intake manifold inlet upgrade was available to relocate the MAP sensor away from oil swirl. Installing this upgrade resolved the issue with codes P0299 and P0098. Additionally, cleaning out oil buildup in the CAC and performing maintenance on the turbocharger and EGR system helped improve engine performance and prevent future issues.
Case #2: Ford P0098
Vehicle Information 2014 Ford F-150 3.5L EcoBoost
Issue + Repair History
- MIL illuminated with code P0098 (IAT Sensor 2 Circuit High).
- No noticeable symptoms reported by the driver.
- Previous repairs: none mentioned.
Other OBD2 Codes + Test Results
- OBD2 Code: P0098 – IAT Sensor 2 Circuit High.
- No additional codes reported.
- Live data shows consistent high voltage readings from the IAT sensor 2.
Mechanic Suggestions
- Inspect the IAT sensor 2 and its wiring for any signs of damage or corrosion.
- Check the IAT sensor 2 connector for proper connection and signs of damage.
- Test the IAT sensor 2 circuit for continuity and voltage drop.
- Inspect the intake air system for any leaks or obstructions that may affect sensor readings.
- Consider replacing the IAT sensor 2 if no other issues are found.
Final Fix After diagnosing the issue and testing the IAT sensor 2 circuit, it was determined that the sensor was faulty, causing the circuit to read high voltage consistently. Replacing the IAT sensor 2 resolved the issue, and the vehicle no longer displayed the P0098 trouble code.
Case #3: Toyota P0098
Vehicle Information 2012 Toyota Camry 2.5L
Issue + Repair History
- Check engine light on with code P0098 (IAT Sensor 2 Circuit High).
- No drivability issues reported by the driver.
- Previous repairs: none mentioned.
Other OBD2 Codes + Test Results
- OBD2 Code: P0098 – IAT Sensor 2 Circuit High.
- No additional codes reported.
- Live data shows elevated voltage readings from the IAT sensor 2.
Mechanic Suggestions
- Inspect the IAT sensor 2 and its wiring for any signs of damage or corrosion.
- Check the IAT sensor 2 connector for proper connection and signs of damage.
- Test the IAT sensor 2 circuit for continuity and voltage drop.
- Inspect the intake air system for any leaks or obstructions that may affect sensor readings.
- Consider replacing the IAT sensor 2 if no other issues are found.
Final Fix Upon diagnosing the issue and testing the IAT sensor 2 circuit, it was evident that the sensor was faulty, causing the circuit to read high voltage consistently. Replacing the IAT sensor 2 resolved the issue, and the vehicle no longer displayed the P0098 trouble code.
How to diagnose P0098
I made you an overview of solving this DTC, based on all the advice that was suggested by certified mechanics to address this issue in previously mentioned service cases.
| Diagnostic Step | Brief Explanation |
|---|---|
| Inspect the IAT sensor and its wiring | Checks for any physical damage or corrosion that could lead to incorrect voltage readings. |
| Check the IAT sensor connector | Ensures the sensor is properly connected and there’s no damage to the connector itself. |
| Test the IAT sensor circuit | Identifies if there’s a short to power or other electrical issues causing the high voltage input. |
| Inspect the intake air system | Looks for leaks or blockages that could affect air temperature readings. |
| Consider replacing the IAT sensor | Advised if the sensor is determined to be the source of the high input signal. |
Car Diagnostics Training
- Car Electrical basics
- OBD-II scanner basics
- How to use an OBD reader
- Introduction to a Bi-directional Scan tool
- OBD scanner buyer’s guide + discounts
I test OBD-II scanners and make DIY Engine diagnostics guides to help you solve your car problems without having to depend on the mechanic. A lot of them will try to scam you or are just no help at all. About Juraj Lukacko