Code
P00A8
Generic
P — Powertrain
Intake Air Temperature Sensor 2 Circuit High Bank 2
Views:
UK: 25
EN: 48
RU: 28
AI status
Completed
Completed
100%
Causes
- Open or damaged IAT sensor 2 wiring (broken conductor, connector backing out)
- Corroded or loose connector at the sensor or PCM
- Sensor element failed (open or internally high resistance)
- Short to voltage (sensor signal shorted to 5V/ignition voltage)
- Poor or missing ground/reference from PCM
- Water intrusion or contamination in connector
Symptoms
- Check Engine Light (MIL) illuminated, with stored P00A8
- Unusual IAT readings on scan tool (stuck high or implausible values)
- Possible poor cold-start fuel control or drivability issues if ECU uses IAT for fueling
- Reduced fuel economy or elevated emissions in some cases
- Engine may go to default/limp IAT value (affecting air–fuel trim)
What to check
- Read trouble code and freeze-frame data; note engine conditions when code set
- Scan live data: monitor IAT Sensor 2 voltage and temperature value, compare with IAT Sensor 1 and ambient air temp
- Check for related codes (other bank 2 sensor/circuit failures)
- Visually inspect IAT sensor 2 connector, wiring harness, and routing for damage, corrosion, or pin issues
- Backprobing: with key on (engine off) measure reference voltage and signal voltage at sensor connector
- Measure continuity/ resistance between sensor signal pin and PCM pin, and check for shorts to battery/ignition and ground
Signal parameters
- Typical IAT signal: voltage range approx. 0.2–4.8 V (varies by manufacturer)
- At normal ambient temps the signal is typically in the mid-range (often around ~2–3 V at ~20–25°C)
- Circuit-high condition: signal voltage near the upper rail (close to reference voltage, e.g. ≈5 V) or reading indicates extremely cold/unrealistic temperature
- IAT sensors are usually NTC thermistors (resistance decreases as temperature rises) — expected resistance falls with increasing temperature (consult vehicle spec)
Diagnostic algorithm
- Verify code and capture freeze-frame/live data. Compare IAT Sensor 2 value to IAT Sensor 1 and ambient/air intake temp reading for plausibility.
- Perform visual inspection of sensor 2 and harness on Bank 2: look for chafing, heat damage, exposed conductors, corrosion, or loose connectors.
- With key ON (engine OFF) backprobe sensor connector: check reference voltage (usually ~5 V) and ground. Record signal voltage. If reference or ground missing, diagnose power/ground circuits.
- With connector unplugged, measure sensor resistance at ambient temp. If open or out of expected resistance curve, replace sensor.
- If sensor resistance is OK, check continuity from sensor signal pin to PCM pin and check for shorts to battery voltage or ground. Repair wiring as needed.
- If signal is high at the PCM but wiring to sensor is OK and sensor checks good, inspect PCM connector and grounds. Consider PCM fault only after wiring and sensor verified.
- After repair or replacement, clear codes and perform test drive/monitor live data to confirm code does not return and values track with temperature changes.
- Safety note: avoid probing connectors with ignition on for extended periods; take battery disconnect precautions if removing electrical components.
Likely causes
- Connector corroded or pins pushed out at IAT sensor or PCM
- Broken wire in harness near flex points or heat exposure on Bank 2 side
- IAT sensor open or internally failed
- Short to 5V supply or poor ground to PCM
Fault status
Status
Intake Air Temperature (IAT) Sensor 2 Circuit High — Bank 2 detected. PCM sees abnormally high sensor signal (open/high-resistance circuit or short to reference voltage).
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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