If your OBD-II scanner displays P0098, your vehicle’s Engine Control Module (ECM) or Powertrain Control Module (PCM) has detected that the Intake Air Temperature (IAT) Sensor 2 circuit voltage is higher than the manufacturer’s acceptable operating range.
The generic OBD-II definition for P0098 is:
Intake Air Temperature Sensor 2 Circuit High
Unlike P0097, which indicates a low-voltage condition caused by a short-to-ground or low resistance, P0098 means the PCM is receiving an abnormally high voltage signal from Intake Air Temperature Sensor 2. In most cases, this tells the PCM that the intake air is extremely cold—even when it clearly isn’t.
Because Intake Air Temperature sensors are Negative Temperature Coefficient (NTC) thermistors, resistance increases as temperature decreases. If the circuit becomes open or develops excessive resistance, the PCM interprets the high voltage as an unrealistically low intake air temperature.
Accurate intake air temperature information is essential for calculating fuel delivery, ignition timing, turbocharger boost, emissions, and overall engine performance. When Sensor 2 sends incorrect information, the PCM may command an overly rich air/fuel mixture, reduce performance, or illuminate the Check Engine Light.
Fortunately, P0098 is usually caused by relatively simple electrical problems such as an unplugged connector, broken wiring, excessive circuit resistance, or a failed Intake Air Temperature sensor.
Alternate Manufacturer Definitions
Depending on the manufacturer or scan tool, P0098 may also appear as:
- Intake Air Temperature Sensor 2 Circuit High Input
- IAT Sensor 2 Circuit High
- Intake Temperature Sensor 2 High Voltage
- Charge Air Temperature Sensor Circuit High
- Air Charge Temperature Sensor High Input
- Intake Air Sensor 2 High Voltage
- Turbo Intake Temperature Sensor Circuit High
- Secondary Intake Air Temperature Sensor Circuit High
Although the wording varies slightly, every definition indicates the PCM has detected higher-than-normal voltage in the Intake Air Temperature Sensor 2 circuit.
P0098 Quick Facts
| Item | Information |
|---|---|
| DTC | P0098 |
| Description | Intake Air Temperature Sensor 2 Circuit High |
| Category | Powertrain |
| System | Air Intake / Engine Management |
| Severity | Moderate |
| Safe to Drive? | Usually Yes |
| Common Causes | Open circuit, unplugged sensor, broken wiring, failed sensor, connector damage |
| Estimated Repair Cost | $75–$900+ |
What Does the P0098 Code Mean?
The PCM continuously monitors Intake Air Temperature Sensor 2 to determine the temperature of the incoming air after it passes through the intake system or intercooler.
That information helps calculate:
- Fuel injector pulse width
- Ignition timing
- Air/fuel ratio
- Turbocharger boost control
- Emissions operation
- Engine load
When the PCM detects that Sensor 2 voltage exceeds the expected operating range, it stores P0098 and turns on the Check Engine Light.
Because the PCM believes intake air is much colder than it actually is, it may increase fuel delivery unnecessarily.
How Intake Air Temperature Sensors Work
Most Intake Air Temperature sensors are simple thermistors supplied with a 5-volt reference.
As intake temperature changes:
The sensor resistance changes.
The PCM monitors the return voltage.
Typical operation:
Cold Air
- High resistance
- High voltage
- Low calculated temperature
Hot Air
- Low resistance
- Low voltage
- High calculated temperature
When the circuit becomes open, voltage often remains close to the full 5-volt reference.
The PCM interprets this as extremely cold intake air and stores P0098.
What Does “Circuit High” Mean?
A Circuit High code means the PCM is receiving higher voltage than expected.
This does not automatically mean the engine is running cold.
Instead, it usually indicates an electrical problem preventing the sensor from pulling voltage downward.
Common causes include:
- Open circuit
- Broken signal wire
- Unplugged sensor
- Connector corrosion
- High circuit resistance
- Failed sensor
- Loose connector
- Internal PCM fault (rare)
Where Is Intake Air Temperature Sensor 2 Located?
The location varies by manufacturer.
Common mounting locations include:
Charge Pipe
Many turbocharged engines mount Sensor 2 inside the aluminum charge pipe.
After the Intercooler
Many boosted engines monitor air temperature after intercooler cooling.
Intake Manifold
Some naturally aspirated engines place the sensor inside the intake manifold.
Integrated MAP/IAT Assembly
Many late-model vehicles combine the MAP sensor and Intake Air Temperature sensor into one housing.
Always identify the correct sensor before replacement.
How the PCM Detects P0098
The PCM constantly compares Intake Air Temperature Sensor 2 against several other sensors.
These include:
- Intake Air Temperature Sensor 1
- Ambient Air Temperature
- Engine Coolant Temperature
- Mass Air Flow Sensor
- Manifold Absolute Pressure Sensor
- Engine RPM
- Engine Load
If Sensor 2 suddenly reports an impossible cold-air temperature because of excessive circuit voltage, the PCM recognizes the fault and stores P0098.
Difference Between P0095 Through P0099
These closely related codes identify different Intake Air Temperature Sensor 2 faults.
| Code | Description |
|---|---|
| P0095 | Intake Air Temperature Sensor 2 Circuit |
| P0096 | Intake Air Temperature Sensor 2 Performance |
| P0097 | Intake Air Temperature Sensor 2 Circuit Low |
| P0098 | Intake Air Temperature Sensor 2 Circuit High |
| P0099 | Intake Air Temperature Sensor 2 Circuit Intermittent |
An easy way to remember them:
P0095
General electrical fault.
P0096
Performance or rationality problem.
P0097
Voltage too low.
P0098
Voltage too high.
P0099
Signal intermittently disappears.
Symptoms of P0098
The symptoms vary depending on how much the faulty sensor affects PCM calculations.
Common symptoms include:
- Check Engine Light
- Rich air/fuel mixture
- Reduced fuel economy
- Rough idle
- Hard starting
- Poor throttle response
- Black smoke from exhaust (rich condition)
- Engine hesitation
- Increased emissions
- Reduced turbocharger performance
- Cooling fan operation abnormalities
- Failed emissions inspection
- Slight loss of engine power
Some vehicles may exhibit no noticeable drivability issues beyond the illuminated Check Engine Light.
Can P0098 Cause Poor Fuel Economy?
Yes.
If the PCM incorrectly believes the intake air is extremely cold, it may command a richer fuel mixture.
This often results in:
- Increased fuel consumption
- Carbon buildup
- Sooty spark plugs
- Higher emissions
Can P0098 Cause Hard Starting?
Yes.
Incorrect intake temperature calculations can affect cold-start fuel delivery, leading to:
- Extended crank time
- Rough startup
- Rich idle
- Temporary stalling
Can P0098 Affect Turbocharger Performance?
Absolutely.
Turbocharged engines depend on accurate charge air temperature readings for boost management.
False low-temperature readings may cause:
- Reduced boost efficiency
- Altered ignition timing
- Torque management intervention
- Reduced engine performance
Can P0098 Cause Rough Idle?
Yes.
Improper fuel calculations caused by incorrect intake air temperature readings may produce:
- Rough idle
- Hesitation
- Engine vibration
- Rich idle conditions
Is P0098 Serious?
P0098 is considered a moderate-severity diagnostic trouble code.
Although many vehicles remain drivable, prolonged operation with incorrect intake temperature data can contribute to:
- Reduced fuel economy
- Increased emissions
- Carbon buildup
- Poor engine performance
- Additional diagnostic trouble codes
Repairing the fault promptly helps prevent further drivability issues.
Can You Drive with P0098?
Usually, yes.
If the vehicle:
- Starts normally
- Runs smoothly
- Does not enter reduced-power mode
- Has acceptable throttle response
Short-term driving is generally safe.
However, prolonged operation with an excessively rich fuel mixture can damage the catalytic converter over time.
25 Common Causes of P0098
The most common causes include:
- Failed Intake Air Temperature Sensor 2
- Open signal wire
- Broken wiring harness
- Unplugged sensor connector
- Connector corrosion
- Loose connector terminals
- High circuit resistance
- Damaged wiring insulation
- Water intrusion
- Oil contamination
- Poor PCM connection
- Damaged PCM connector
- Faulty MAP/IAT combination sensor
- Previous wiring repairs
- Rodent damage
- Broken connector locking tab
- Improper aftermarket intake installation
- Charging system voltage issues
- Faulty Engine Coolant Temperature sensor causing correlation issues
- Faulty Ambient Air Temperature sensor
- Loose engine grounds
- PCM software issue
- Internal PCM failure (rare)
- Low-quality aftermarket replacement sensor
- Incorrect sensor installation
One of the most common causes of P0098 is a sensor connector that has been left unplugged after air filter, intercooler, or turbocharger service, leaving the PCM to see nearly the full 5-volt reference signal.
Unlike P0097, which indicates the sensor signal is too low, P0098 means the PCM is seeing a voltage signal that is higher than expected. In most cases, this is caused by an open circuit, unplugged connector, broken signal wire, excessive circuit resistance, or a failed sensor.
How to Diagnose the P0098 Code
Step 1: Verify the Code
Connect a professional OBD-II scan tool and record:
- Stored DTCs
- Pending DTCs
- Freeze-frame data
- Intake Air Temperature Sensor 1
- Intake Air Temperature Sensor 2
- Ambient Air Temperature
- Engine Coolant Temperature
- Battery voltage
Freeze-frame data often identifies the exact operating conditions when the fault occurred.
Step 2: Check for Additional Trouble Codes
P0098 frequently appears with:
- P0095 Intake Air Temperature Sensor 2 Circuit
- P0096 Intake Air Temperature Sensor 2 Performance
- P0097 Intake Air Temperature Sensor 2 Circuit Low
- P0099 Intake Air Temperature Sensor 2 Circuit Intermittent
- P0101 Mass Air Flow Performance
- P0106 MAP Sensor Performance
- P0112 Intake Air Temperature Circuit Low
- P0113 Intake Air Temperature Circuit High
- P0114 Intake Air Temperature Circuit Intermittent
Multiple intake temperature codes often indicate a broader electrical issue.
Step 3: Perform a Visual Inspection
Inspect the complete Intake Air Temperature Sensor 2 circuit.
Look for:
- Broken wiring
- Disconnected connectors
- Corrosion
- Oil contamination
- Water intrusion
- Pinched harnesses
- Damaged insulation
- Rodent damage
Many P0098 repairs are completed without replacing any components.
Step 4: Verify Sensor Location
Depending on the engine, Intake Air Temperature Sensor 2 may be located:
- After the intercooler
- Inside the charge pipe
- Integrated into the MAP sensor
- Inside the intake manifold
Always verify the correct sensor before beginning repairs.
Step 5: Compare Cold Engine Readings
Allow the vehicle to sit overnight.
Before starting the engine, compare:
- Intake Air Temperature Sensor 1
- Intake Air Temperature Sensor 2
- Ambient Air Temperature
All three temperatures should be nearly identical.
If Sensor 2 reports an extremely low temperature, suspect a circuit-high condition.
Step 6: Inspect the Connector
Disconnect the connector.
Inspect for:
- Loose terminals
- Corrosion
- Bent pins
- Broken locking tabs
- Moisture
- Dirt
An unplugged connector is one of the most common causes of P0098.
Step 7: Verify the 5-Volt Reference
Using a digital multimeter:
Confirm the PCM is supplying the proper reference voltage.
Most systems should measure approximately:
5 volts
Always compare readings with manufacturer specifications.
Step 8: Verify Ground Integrity
Inspect:
- Engine grounds
- Chassis grounds
- PCM grounds
A poor ground can prevent the sensor from pulling the signal voltage down correctly.
Step 9: Test Sensor Resistance
Disconnect the sensor.
Measure resistance across its terminals.
As temperature changes:
- Cold temperatures = higher resistance
- Warm temperatures = lower resistance
Compare results with the factory temperature/resistance chart.
Step 10: Test for an Open Circuit
Disconnect both the PCM connector and the sensor connector.
Measure continuity across the signal wire.
No continuity usually indicates:
- Broken wiring
- Open circuit
- Internal harness damage
Open circuits are among the leading causes of P0098.
Step 11: Inspect Wiring Near Heat Sources
Carefully inspect wiring routed near:
- Turbochargers
- Exhaust manifolds
- Catalytic converters
- Charge pipes
- Heat shields
High temperatures may damage wiring insulation and connectors.
Step 12: Wiggle-Test the Harness
Monitor live scan tool data.
Move the harness while watching Sensor 2.
Look for:
- Sudden temperature changes
- Signal dropouts
- Voltage spikes
Intermittent wiring faults often appear during this test.
Step 13: Inspect the Sensor
Remove Intake Air Temperature Sensor 2.
Check for:
- Cracks
- Physical damage
- Contamination
- Burn marks
Replace the sensor if damaged.
Step 14: Inspect the Intake System
Look for:
- Loose charge pipes
- Damaged intercooler hoses
- Air leaks
- Improper aftermarket installation
Although P0098 is electrical, intake system problems can contribute to inaccurate readings.
Step 15: Test Circuit Continuity
Disconnect:
- PCM connector
- Sensor connector
Measure continuity across every circuit.
High resistance indicates wiring damage requiring repair.
Step 16: Evaluate MAP/IAT Combination Sensors
Many manufacturers combine the MAP and Intake Air Temperature sensors into one assembly.
Verify:
- MAP readings
- Intake temperature readings
A failed combination sensor may require replacement.
Step 17: Verify Charging System Voltage
Low or unstable charging voltage can affect multiple sensors.
Check:
- Battery voltage
- Alternator output
- Charging system performance
Repair charging problems before replacing sensors.
Step 18: Inspect PCM Connectors
Disconnect the PCM following factory procedures.
Inspect for:
- Bent terminals
- Corrosion
- Water intrusion
- Loose pins
PCM connector issues are uncommon but should not be overlooked.
Step 19: Review Technical Service Bulletins (TSBs)
Some manufacturers have issued TSBs involving:
- PCM calibration updates
- Improved sensor connectors
- Wiring harness repairs
- Updated Intake Air Temperature sensors
Always review available TSBs before replacing expensive components.
Step 20: Monitor Live Data During Driving
Observe Intake Air Temperature Sensor 2 during:
- Idle
- Light acceleration
- Highway driving
- Turbocharger boost
Temperature values should change gradually and logically.
Step 21: Compare Sensor 1 and Sensor 2
Small differences are normal.
Large differences often indicate:
- Wiring problems
- Failed sensor
- Connector faults
- Open circuits
Step 22: Inspect Aftermarket Modifications
Check for:
- Cold air intake systems
- Turbocharger upgrades
- Intercooler upgrades
- Modified wiring
- Custom tuning
Improper modifications frequently introduce wiring damage or disconnected sensors.
Step 23: Clear the Code
After completing repairs:
- Clear all DTCs
- Restart the engine
- Verify Intake Air Temperature Sensor 2 readings
Ensure the PCM no longer detects a circuit-high condition.
Step 24: Perform a Road Test
Drive under multiple operating conditions:
- Idle
- City traffic
- Highway cruising
- Moderate acceleration
- Full operating temperature
Monitor live data throughout the drive.
Step 25: Confirm the Repair
Before returning the vehicle:
Verify:
- No stored codes
- No pending codes
- Stable Intake Air Temperature Sensor readings
- Normal fuel trims
- Proper throttle response
- Check Engine Light remains off
Common Repairs for P0098
Depending on the diagnosis, repairs may include:
- Replacing Intake Air Temperature Sensor 2
- Repairing open wiring
- Replacing damaged connectors
- Cleaning corroded terminals
- Repairing broken harnesses
- Replacing MAP/IAT combination sensors
- Repairing charge pipe wiring
- Updating PCM software
- Repairing poor ground connections
- Replacing the PCM (rare)
Estimated Repair Costs
| Repair | Typical Cost |
|---|---|
| Connector repair | $75–$250 |
| Wiring repair | $100–$350 |
| Intake Air Temperature Sensor | $50–$250 |
| Sensor replacement with labor | $125–$400 |
| MAP/IAT sensor assembly | $150–$500 |
| Charge pipe wiring repair | $150–$450 |
| PCM software update | $100–$250 |
| PCM replacement | $900–$2,500+ |
Actual repair costs vary depending on the manufacturer, labor rates, and whether OEM or aftermarket components are used.
Common Diagnostic Mistakes
Avoid these common mistakes:
- Replacing the sensor without testing the wiring
- Ignoring unplugged connectors
- Overlooking open circuits
- Forgetting to compare Sensor 1 and Sensor 2
- Skipping continuity testing
- Ignoring poor ground connections
- Replacing the PCM before completing electrical tests
- Overlooking aftermarket intake modifications
- Ignoring Technical Service Bulletins
- Confusing P0098 with P0097
The majority of P0098 repairs involve open circuits or disconnected connectors, not failed engine computers.
Manufacturer-Specific Notes
Ford
EcoBoost engines commonly experience damaged wiring near the turbocharger and intercooler plumbing. Inspect the harness carefully before replacing the sensor.
General Motors
Many GM engines use an integrated MAP/IAT sensor assembly. Test both functions before replacing the sensor.
Toyota & Lexus
Inspect connectors carefully for corrosion and verify proper terminal engagement before replacing components.
Honda & Acura
Turbocharged Honda engines frequently experience wiring damage after aftermarket intake or intercooler installations.
Nissan & Infiniti
Inspect the intake harness for broken wiring and ensure connectors are fully seated after maintenance.
BMW & MINI
Charge Air Temperature sensors are commonly integrated into boost plumbing. Inspect for oil contamination and damaged wiring before replacement.
Volkswagen & Audi
Verify sensor operation with live scan data and inspect the integrated MAP/IAT assembly for connector damage or excessive resistance.
Mercedes-Benz
Inspect charge air sensor wiring routed near turbochargers, where prolonged heat exposure can damage insulation and connectors.
Hyundai & Kia
Inspect engine wiring near the intake manifold for loose connectors, corrosion, and previous repair work.
Diesel Engines
On turbocharged diesel engines, inspect the charge air temperature sensor wiring carefully. Open circuits frequently occur near intercooler plumbing due to vibration and heat.
Frequently Asked Questions
What does P0098 mean?
P0098 indicates the PCM has detected a higher-than-normal voltage signal from Intake Air Temperature Sensor 2.
Is P0098 serious?
Generally, P0098 is considered a moderate-severity diagnostic trouble code. Although many vehicles remain drivable, delayed repairs can reduce fuel economy, increase emissions, and affect overall engine performance.
Can I drive with a P0098 code?
Yes, in most cases. However, if the engine enters reduced-power mode or develops drivability issues, repairs should be completed promptly.
Does P0098 always mean the sensor is bad?
No. Broken wiring, unplugged connectors, open circuits, poor electrical connections, or excessive circuit resistance commonly trigger this code.
Can an unplugged sensor cause P0098?
Yes. A disconnected Intake Air Temperature Sensor 2 is one of the most common causes of this diagnostic trouble code.
Can broken wiring cause P0098?
Absolutely. An open signal wire often prevents the sensor from pulling the circuit voltage down, resulting in a circuit-high fault.
How much does it cost to repair P0098?
Repair costs typically range from $75 for connector repairs to more than $2,500 for rare PCM replacement.
Will clearing the code fix P0098?
No. Clearing the code only removes the stored fault temporarily. The code will return if the electrical problem remains.
Can a scan tool identify the exact cause?
A scan tool provides valuable live data, but electrical testing with a multimeter is required to locate open circuits, wiring faults, or connector failures.
What is the difference between P0097 and P0098?
P0097 indicates low circuit voltage, while P0098 indicates high circuit voltage from Intake Air Temperature Sensor 2.
Preventative Maintenance
To reduce the likelihood of P0098:
- Inspect Intake Air Temperature sensor connectors during routine service.
- Secure wiring away from hot exhaust and turbocharger components.
- Repair damaged wiring promptly.
- Replace broken connector locking tabs.
- Keep electrical connectors clean and dry.
- Inspect aftermarket intake installations for stretched or disconnected wiring.
- Repair oil leaks that may contaminate connectors.
- Address Check Engine Light warnings promptly before minor electrical issues become major repairs.
Routine inspection of the intake system and engine wiring harness can significantly reduce the risk of circuit-high faults.
Final Thoughts
The P0098 Intake Air Temperature Sensor 2 Circuit High code indicates that the ECM or PCM has detected a voltage signal above the expected operating range from the secondary intake air temperature sensor. In most cases, the cause is an electrical fault—such as an open circuit, unplugged connector, broken wiring, or excessive resistance—rather than a problem with actual intake air temperature.
A systematic diagnosis that includes inspecting the wiring harness, testing circuit continuity, verifying the 5-volt reference and ground circuits, and comparing live data from related sensors will usually identify the root cause while preventing unnecessary replacement of otherwise functional components.
