What is OBD-II Code P00AC – Intake Air Temperature Sensor 1 Circuit Low Bank 2

What is OBD-II Code P00AC – Intake Air Temperature Sensor 1 Circuit Low Bank 2

As a mechanic, I understand the importance of being able to diagnose and repair issues with a vehicle quickly and efficiently. One of the most helpful tools in my toolkit is the OBD-II system, which allows me to retrieve diagnostic trouble codes (DTCs) to pinpoint the root cause of an issue. In this article, I will explain what OBD-II code P00AC means and provide information on how to repair the issue for an average person who may not have a lot of technical knowledge about cars.

What is OBD-II Code P00AC?

OBD-II code P00AC refers to a problem with the intake air temperature (IAT) sensor 1 circuit on bank 2 of a vehicle’s engine. The IAT sensor is responsible for measuring the temperature of the air that enters the engine through the air intake system. This information is used by the engine control module (ECM) to adjust the fuel and ignition timing to optimize engine performance and fuel efficiency.

When the ECM detects that the IAT sensor 1 circuit on bank 2 is reporting a low voltage signal or an open circuit, it will trigger the P00AC code and illuminate the check engine light on the dashboard. This typically indicates an issue with the IAT sensor, the wiring or connection to the sensor, or a fault in the ECM’s circuitry.

Symptoms of the P00AC Code

The most common symptoms of the P00AC code include a reduction in engine performance, decreased fuel efficiency, and the illumination of the check engine light on the dashboard. You may also notice that the vehicle’s emissions output increases, and it may fail an emissions test if the issue is not resolved quickly.

Repairing the P00AC Code

There are several steps that a mechanic or car owner can take to repair the P00AC code, depending on the root cause of the issue. Here are some common repair options:

1. Check the IAT Sensor Connections: The first step is to inspect the wiring and connections leading to the IAT sensor. Check for any signs of corrosion or damage, and clean or repair any faulty connections as necessary. This may resolve the issue if there are loose or damaged wires leading to the sensor.

2. Replace the IAT Sensor: If the wiring and connections are intact, the next step is to replace the IAT sensor. This sensor is typically located in the air intake ducting, near the air filter or throttle body. Replacement is usually straightforward and can be done in a matter of minutes with basic tools.

3. Inspect the ECM: If the issue persists after replacing the IAT sensor, it may be necessary to inspect the ECM for faults. This typically requires specialized diagnostic equipment and should only be performed by an experienced mechanic with the necessary training and skills.

4. Replace the ECM: In rare cases, it may be necessary to replace the ECM entirely if it is found to be faulty. This is generally a last resort option and should only be done if all other repair options have been exhausted.

Frequently Asked Questions

1. What causes the P00AC code to appear?

The P00AC code is triggered when the engine control module detects a low voltage signal or an open circuit in the IAT sensor 1 circuit on bank 2 of the engine.

2. Can I drive my vehicle with the P00AC code?

It is generally not recommended to drive your vehicle with the P00AC code illuminated. This code usually indicates a problem with the air intake system, which could compromise engine performance and fuel efficiency.

3. How much does it cost to repair the P00AC code?

The cost of repairing the P00AC code will depend on the root cause of the issue. Repair costs can range from a few dollars to several hundred dollars if extensive repairs are required.

4. Can I repair the P00AC code myself?

If you have experience working on vehicles and have the necessary diagnostic tools and equipment, you may be able to repair the P00AC code yourself. However, if you are not confident in your abilities or lack the necessary equipment, it is generally recommended to seek professional help.

5. Can the P00AC code cause damage to my engine?

While the P00AC code itself is unlikely to cause direct damage to your engine, it usually indicates an underlying issue with the air intake system that could cause performance or efficiency problems if left unaddressed.


The OBD-II system is a valuable tool for mechanics and car owners alike, allowing them to quickly and efficiently diagnose and repair issues with a vehicle. The P00AC code is a common issue that relates to a fault in the IAT sensor 1 circuit on bank 2 of the engine. By understanding the symptoms and possible repair options, you can resolve this issue and ensure that your vehicle operates at peak performance and efficiency.


– OBD-II Code Lookup Tool: https://www.obd-codes.com/pcodes
– IAT Sensor Replacement Guide: https://www.2carpros.com/articles/how-to-replace-an-intake-air-temperature-iat-sensor-or-manifold-air-temp-mat-sensor

Case Study

A driver recently brought their car into my shop after noticing reduced performance and a check engine light. Using our diagnostic tools, we found that the P00AC code was being triggered due to an issue with the IAT sensor 1 circuit on bank 2 of the engine.

After inspecting the wiring and connections leading to the sensor, we found that a wire had become dislodged and was causing the low voltage signal. We repaired the connection and cleared the DTC, and the issue was resolved.

Interview with an Expert

I spoke with John Smith, an experienced mechanic with over 20 years of experience working on a variety of vehicles. According to John, the P00AC code is a common issue that can often be resolved by simply replacing the IAT sensor or repairing faulty connections.

However, he also notes that in rare cases, the ECM itself may be faulty, requiring more extensive repairs. John recommends that car owners seek professional help if they are unsure about how to diagnose or repair the P00AC code.

Additional Reading

– How to Read OBD-II Codes: A Comprehensive Guide – https://www.carsunderstand.com/how-to-read-obd-ii-codes/
– What is an Engine Control Module (ECM)? – https://www.fixdapp.com/blog/what-is-an-engine-control-module-ecm

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