P0098 — Intake Air Temperature Sensor 2 Circuit High Bank 1

Diagnostic algorithm

1. Retrieve codes and freeze-frame; note whether the code is current or historic and any related codes (IAT1, ECT, MAF).
2. Visually inspect the IAT2 sensor and wiring harness at the intake and along the run to the ECM for damage, corrosion, or contamination. Repair obvious issues.
3. With key ON (engine OFF) backprobe the sensor connector: identify signal, reference (if present), and ground. Verify reference voltage present (typically ~5 V or ECU-specific reference) and good ground.
4. Measure the sensor signal voltage. A circuit-high fault typically shows signal near the reference/pull-up (≈4.5–5.0 V). If so, check for open circuit or short to battery voltage.
5. Disconnect the sensor and measure its resistance across the terminals at ambient temperature. Compare to expected thermistor behavior (resistance should be finite and decrease with heat). An open or infinite resistance indicates a failed sensor.
6. Check continuity between the sensor connector and the ECM input pin for opens. Also check for unintended continuity (shorts) to battery positive on the signal/reference wire and for shorts to other circuits.
7. If wiring and sensor check good, swap with a known-good identical sensor (if available) or temporarily connect a compatible sensor to verify operation.
8. If the circuit and sensor are good but fault persists, check for ECM input faults or perform ECU diagnostics per manufacturer procedures.
9. Clear codes and perform a road or run test to verify repair. Re-scan to confirm no return of P0098.