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P0098 Code Explained: Intake Air Temperature Sensor 2 Circuit High Causes, Symptoms & Fixes

P0098 Intake Air Temperature Sensor 2 Circuit High illustration showing an IAT sensor, open wiring harness, unplugged connector, charge pipe, turbocharger, and Check Engine warning light

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:

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

ItemInformation
DTCP0098
DescriptionIntake Air Temperature Sensor 2 Circuit High
CategoryPowertrain
SystemAir Intake / Engine Management
SeverityModerate
Safe to Drive?Usually Yes
Common CausesOpen 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:

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

Hot Air

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:

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:

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.

CodeDescription
P0095Intake Air Temperature Sensor 2 Circuit
P0096Intake Air Temperature Sensor 2 Performance
P0097Intake Air Temperature Sensor 2 Circuit Low
P0098Intake Air Temperature Sensor 2 Circuit High
P0099Intake 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:

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:

Can P0098 Cause Hard Starting?

Yes.

Incorrect intake temperature calculations can affect cold-start fuel delivery, leading to:

Can P0098 Affect Turbocharger Performance?

Absolutely.

Turbocharged engines depend on accurate charge air temperature readings for boost management.

False low-temperature readings may cause:

Can P0098 Cause Rough Idle?

Yes.

Improper fuel calculations caused by incorrect intake air temperature readings may produce:

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:

Repairing the fault promptly helps prevent further drivability issues.

Can You Drive with P0098?

Usually, yes.

If the vehicle:

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:

  1. Failed Intake Air Temperature Sensor 2
  2. Open signal wire
  3. Broken wiring harness
  4. Unplugged sensor connector
  5. Connector corrosion
  6. Loose connector terminals
  7. High circuit resistance
  8. Damaged wiring insulation
  9. Water intrusion
  10. Oil contamination
  11. Poor PCM connection
  12. Damaged PCM connector
  13. Faulty MAP/IAT combination sensor
  14. Previous wiring repairs
  15. Rodent damage
  16. Broken connector locking tab
  17. Improper aftermarket intake installation
  18. Charging system voltage issues
  19. Faulty Engine Coolant Temperature sensor causing correlation issues
  20. Faulty Ambient Air Temperature sensor
  21. Loose engine grounds
  22. PCM software issue
  23. Internal PCM failure (rare)
  24. Low-quality aftermarket replacement sensor
  25. 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:

Freeze-frame data often identifies the exact operating conditions when the fault occurred.

Step 2: Check for Additional Trouble Codes

P0098 frequently appears with:

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:

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:

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:

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:

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:

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:

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:

Open circuits are among the leading causes of P0098.

Step 11: Inspect Wiring Near Heat Sources

Carefully inspect wiring routed near:

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:

Intermittent wiring faults often appear during this test.

Step 13: Inspect the Sensor

Remove Intake Air Temperature Sensor 2.

Check for:

Replace the sensor if damaged.

Step 14: Inspect the Intake System

Look for:

Although P0098 is electrical, intake system problems can contribute to inaccurate readings.

Step 15: Test Circuit Continuity

Disconnect:

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:

A failed combination sensor may require replacement.

Step 17: Verify Charging System Voltage

Low or unstable charging voltage can affect multiple sensors.

Check:

Repair charging problems before replacing sensors.

Step 18: Inspect PCM Connectors

Disconnect the PCM following factory procedures.

Inspect for:

PCM connector issues are uncommon but should not be overlooked.

Step 19: Review Technical Service Bulletins (TSBs)

Some manufacturers have issued TSBs involving:

Always review available TSBs before replacing expensive components.

Step 20: Monitor Live Data During Driving

Observe Intake Air Temperature Sensor 2 during:

Temperature values should change gradually and logically.

Step 21: Compare Sensor 1 and Sensor 2

Small differences are normal.

Large differences often indicate:

Step 22: Inspect Aftermarket Modifications

Check for:

Improper modifications frequently introduce wiring damage or disconnected sensors.

Step 23: Clear the Code

After completing repairs:

Ensure the PCM no longer detects a circuit-high condition.

Step 24: Perform a Road Test

Drive under multiple operating conditions:

Monitor live data throughout the drive.

Step 25: Confirm the Repair

Before returning the vehicle:

Verify:

Common Repairs for P0098

Depending on the diagnosis, repairs may include:

Estimated Repair Costs

RepairTypical 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:

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:

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.

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