What is the P00AD Code?
The P00AD trouble code is a generic powertrain code (OBD-II). It indicates that the Powertrain Control Module (PCM) has detected an abnormally high signal voltage (> 5 volts) from the Intake Air Temperature (IAT) sensor on the engine’s Bank 2. Bank 2 refers to the side of the engine that does not contain cylinder number 1.
IAT Sensor Operation
The PCM sends a 5-volt reference voltage to the IAT sensor. This sensor is a thermistor: its electrical resistance varies with the air temperature. The lower the temperature, the higher the resistance and signal voltage. A voltage above 5 volts is physically impossible and signals an anomaly to the PCM, which then triggers the P00AD code.
Symptoms of the P00AD Code
This code is often accompanied by the illumination of the Malfunction Indicator Lamp (MIL) on the dashboard. In most cases, there are no other noticeable symptoms (loss of power, stalling). The engine may enter a limp mode to protect itself.
Possible Causes of the Fault
- 📛 Faulty IAT Sensor: Internal failure of the thermistor (most common cause).
- 🔌 Connection Problem: Loose, corroded, or oxidized sensor connector.
- ⚡ Wiring Problem: Short to voltage in the signal circuit or an open ground circuit.
- 🧵 Electrical Interference: The sensor harness is routed too close to high-voltage cables (spark plugs, alternator).
- 🖥️ PCM Failure: Rare, but should not be ruled out after checking all other components.
Related Codes
Other codes related to the Bank 2 IAT sensor circuit may appear:
- P00AA: Circuit Low
- P00AB: Range/Performance Problem
- P00AC: Value Low
- P00AE: Intermittent/Erratic Circuit
Diagnosis and Solutions
⚠️ Warning: These procedures require knowledge of automotive mechanics and the use of a diagnostic tool (scan tool) and a multimeter (DVOM). If you are not comfortable, consult a professional mechanic.
- Diagnostic Tool Check: Observe the live data from the IAT sensor. A reading below -30°C indicates a problem (open circuit).
- Wiring Test:
- Disconnect the IAT sensor connector.
- Place a jumper wire between the signal pin and the ground pin on the harness side of the connector.
- If the reading on the diagnostic tool shows a very high value (e.g., > 140°C), the wiring is healthy and the sensor is most likely faulty.
- If the reading does not change, check the continuity of the wires (signal and ground) and the presence of the 5V reference voltage using a multimeter.
- Replacement: If the wiring and reference voltage are correct, replace the Bank 2 IAT sensor. After replacement, clear the codes and perform a drive cycle to verify that the fault does not return.
Conclusion
The P00AD code is often resolved by replacing the faulty IAT sensor. However, a thorough check of the connector and wiring is essential to avoid an unnecessary replacement. For an accurate diagnosis and a reliable repair, do not hesitate to contact a partner garage to get a personalized quote.