What is OBD-II Code P2ADD – Reductant Tank Temperature Sensor B Circuit Intermittent/Erratic

What is OBD-II Code P2ADD – Reductant Tank Temperature Sensor B Circuit Intermittent/Erratic

If you are experiencing a fault code that reads P2ADD on your OBD-II scanner, there is no need to panic. This code indicates that there is a problem with the reductant tank temperature sensor B circuit intermittent/erratic. The reductant tank temperature sensor plays a crucial role in ensuring that your vehicle exhaust system is operating efficiently and effectively. In this article, we will provide you with a detailed description of what P2ADD means, the causes, symptoms, and how to fix it.

Causes of P2ADD

P2ADD is a common error code in diesel engines that use SCR (Selective catalytic reduction) technology. The SCR reduces nitrogen oxide emissions in diesel engines by injecting a urea solution commonly known as Diesel Exhaust Fluid (DEF) into the exhaust stream. A reductant tank temperature sensor B circuit fault will prevent the SCR from operating effectively, leading to increased NOx emissions.

The most common cause of P2ADD error codes is a faulty reductant tank temperature sensor. A damaged or worn-out sensor will not provide an accurate reading of the DEF (diesel exhaust fluid) temperature, causing the sensor to provide intermittent or erratic readings, triggering the P2ADD code. Power supply or software issues affecting the sensor can also lead to a P2ADD error code.

Symptoms of P2ADD

If you are experiencing a P2ADD error code, you will commonly notice the engine warning light illuminate on your dashboard. The warning light illuminates on the dashboard to alert the driver of an emissions control system malfunction. If you ignore this warning and continue to drive your vehicle, you may begin to experience reduced engine performance. The reduction in engine performance is due to the engine controller detecting the error and activating a limp-home mechanism to protect the engine from further damage.

How to Fix P2ADD

The first step in fixing the P2ADD error code is to diagnose the problem accurately. A qualified mechanic will use specialized equipment to read the error code and determine the exact cause of the fault. Once the problem has been identified, the technical expert will provide you with a detailed list of the repairs required.

If the cause of the P2ADD error code is a defective sensor, the mechanic will replace the sensor with a new one. It is crucial to ensure that the replacement sensor is of high quality and is OEM certified to avoid further issues with your vehicle’s emissions control system.

In some cases, the error code could be a result of a wiring fault or software issue. The mechanic will check the system’s power supply and wiring for any visible damage or loose connections. The mechanic will also check the software and update it accordingly to fix the error code.

In summary, the P2ADD error code can be a cause for concern, but there is no need to panic. It is essential to diagnose the problem correctly, locate the root cause of the P2ADD error, and address the issue. In most cases, the repair is relatively straightforward and can be done by a qualified mechanic. With the right repair, your vehicle will be back to operating efficiently, safely, and effectively.


1. What is the reductant tank temperature sensor?
Ans. The reductant tank temperature sensor is responsible for measuring the temperature of the Diesel Exhaust Fluid (DEF) within the reductant tank, which helps improve the vehicle’s environmental performance.

2. What is a reductant tank?
Ans. A reductant tank houses Diesel Exhaust Fluid (DEF), which reduces the amount of nitrogen oxide (NOx) emitted by diesel engines.

3. What is Diesel Exhaust Fluid (DEF)?
Ans. DEF is a urea-based solution used in diesel engines to reduce the amount of nitrogen oxide (NOx) emissions produced.

4. Can I continue to drive my car if I get a P2ADD error code?
Ans. It is not advisable to keep driving your vehicle if you get a P2ADD error code because ignoring it can cause your vehicle engine performance reduced, leading to further damage.

5. Can I replace the reductant tank temperature sensor myself?
Ans. It is not recommended to replace the reductant tank temperature sensor yourself unless you have the technical know-how and specialized equipment. A qualified and experienced mechanic is best to handle these types of repairs.


A P2ADD error code on your OBD-II scanner can be an indication of a problem with your vehicle’s reductant tank temperature sensor. It is crucial to accurately diagnose the issue and fix it promptly to avoid further damage to your vehicle. If you experience this issue, consult a qualified and experienced mechanic who will diagnose the fault correctly and make the necessary repairs. Remember, it’s essential to ensure your vehicle is operating safely, efficiently, and effectively.

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