⚡
"High" voltage means the signal sees full 5V reference - usually an open wire or unplugged sensor. The simplest test: unplug, jumper the connector pins, and the code should change to a "low" code. See IAT sensors on Amazon ↗
🗺️ Where Is the Problem?
Blueprint view - P0098 fault zone in the engine and emissions control system
These are statistical causes across ALL vehicles - your exact car may rank differently
For example, on a Honda 4-cyl the downstream O2 sensor causes P0098 64% of the time, but on a GM 5.3L V8 the catalytic converter is the cause 71% of the time. Get a probability ranking built specifically for your year, make, model, and mileage.
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🎯 Top Causes & Probability
45%
#1 - Most Likely
Open IAT2 Sensor
The thermistor has burned open inside the sensor body. The signal wire floats up to 5V and the ECM reads a max-out hot temp. Replace the sensor.
🔧 Part
$20–$80
👨🔧 Labor
$0–$60
⚡ DIY Difficulty
Easy
35%
#2 - Check First
Open Signal Wire or Connector
A broken wire, corroded pin, or unseated connector breaks the circuit between sensor and ECM. Wiggle test the harness while watching live data to confirm.
🔧 Part
$10–$40
👨🔧 Labor
$60–$160
⚡ DIY Difficulty
Medium
15%
#3 - Less Common
Open Sensor Ground
A bad ECM ground or chassis ground for the sensor reference makes the signal pin always read high. Check ground integrity at the chassis tie points.
🔧 Part
$5–$30
👨🔧 Labor
$60–$140
⚡ DIY Difficulty
Medium
🚗 Most Affected Vehicles
🔧 Step-by-Step Diagnosis
- Jumper the IAT2 connector pins - With the engine off, jumper the two pins. Live data should drop to a high-temp reading; if it stays at the ceiling value, the wiring is open.
- Check sensor ground - Verify continuity from the sensor's ground pin to chassis. Greater than 1Ω needs cleaning.
📍 Find a Trusted Shop Near You
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Tips for Choosing a Shop
- Ask if they charge a diagnostic fee and whether it applies toward the repair
- Request a written estimate before approving any work
- Ask specifically about the part brand - OEM vs. aftermarket matters for this code
- Check Google reviews for recent mentions of the specific repair you need