P00A8 - Intake Air Temperature Sensor 2 Circuit High Bank 1
Last updated:
System
Powertrain (Engine & Gearbox)
Related Fault Codes
Technical Description
P00A8 is stored when the Engine Control Module (ECM) detects a voltage from the Intake Air Temperature Sensor 2 (IAT2) that exceeds the maximum calibrated limit, typically above 4.6V - 4.8V. On forced induction engines, IAT2 is located after the charge air cooler (intercooler) to monitor the density of the compressed air. As the sensor is an NTC thermistor, a 'Circuit High' condition usually indicates an open circuit or high resistance. The ECM perceives this as an implausibly low temperature (e.g., -40°F/C) and will default to a failsafe map to protect the engine, often limiting boost pressure.
Possible Causes
Open circuit in the signal or ground wire to the IAT2 sensor.
Faulty IAT2 sensor (internal open or short to voltage).
Corrosion or backed-out pins in the sensor or ECM connector.
Faulty Engine Control Module (ECM) internal circuitry.
Symptoms
Recommended Solution
- VISUAL INSPECTION: Inspect the wiring harness near the IAT2 sensor for chafing or heat damage. Check the connector for corrosion or bent pins.
- LIVE DATA ANALYSIS: Use a scan tool to monitor IAT2 temperatures. If it reads -40°F/C, the circuit is likely open.
- VOLTAGE TEST: Disconnect the sensor. With ignition ON, check for a 5V reference signal at the harness connector. If missing, check wiring continuity to the ECM.
- RESISTANCE TEST: Measure the sensor resistance. Values vary by temperature (e.g., 2k-3k Ohms at 68°F/20°C). An 'OL' reading confirms a failed sensor.
- GROUND CHECK: Ensure the ground pin in the connector has continuity to the engine ground (close to 0 Ohms).
- REPLACEMENT: If wiring and ground are verified but the sensor output is incorrect, replace the IAT2 sensor.
Mechanic's Tip
Before replacing expensive components, always double-check wiring and connections. 80% of all sensor faults are actually due to corroded contacts or broken wires.
Do you also have
other fault codes?
See how P00A8 connects with your other fault codes. Our advanced analysis tool identifies causal relationships and root causes directly.