What is OBD-II Code P261B – Coolant Pump B Control Circuit Performance/Stuck Off

What is OBD-II Code P261B – Coolant Pump B Control Circuit Performance/Stuck Off

As a mechanic, one of the most common issues that people come to me with is a check engine light that has lit up on their dashboard. This can be a frustrating experience, especially for those who do not have much technical knowledge about cars. One of the codes that I see regularly is OBD-II Code P261B – Coolant Pump B Control Circuit Performance/Stuck Off. In this article, I will explain what this code means, its causes, and how to repair it.

What is OBD-II Code P261B?

OBD-II Code P261B refers to a malfunction in the coolant pump B control circuit. The coolant pump is responsible for circulating the coolant through the engine to prevent overheating. The Engine Control Module (ECM) monitors the coolant pump circuit’s performance and will trigger the check engine light if it detects a problem.

Causes of OBD-II Code P261B

There are several potential causes of OBD-II Code P261B. The most common include:

1. Faulty coolant pump: A coolant pump that is malfunctioning or not working correctly can trigger this error code. The pump may be stuck or may not be able to provide enough coolant flow to keep the engine at the proper temperature.

2. Problems with the coolant pump wiring: A problem with the wiring in the coolant pump circuit can also trigger this code. This could be caused by a break in the circuit, a loose or corroded connection, or a damaged wire.

3. Issues with the coolant temperature sensor: The coolant temperature sensor is responsible for sending information about the engine’s temperature to the ECM. If this sensor is not working correctly, it can trigger the P261B code.

4. Malfunctioning ECM: Finally, a malfunctioning ECM can also trigger this code. While this is less common, it is still a possibility.

How to Repair OBD-II Code P261B

Repairing OBD-II Code P261B involves diagnosing the underlying issue and correcting it. Here are the steps you can take to repair this error code:

1. Diagnose the problem: The first step is to use a diagnostic tool to determine the cause of the error code. This can be done by connecting a scanner to the car and reading the code.

2. Check the coolant pump and wiring: Once you know the cause of the error code, you can check the coolant pump and wiring to see if they are functioning correctly. Look for any signs of damage or wear and tear. If the pump is damaged or not working, it will need to be replaced. If there is a problem with the wiring, it will need to be repaired or replaced.

3. Test the coolant temperature sensor: If the coolant pump and wiring are functioning correctly, you may need to test the coolant temperature sensor. This can be done using a multimeter or other diagnostic tool. If the sensor is not working correctly, it will need to be replaced.

4. Replace the ECM: Finally, if none of the above steps fix the error code, you may need to replace the ECM. This is a more complex and expensive repair and should only be done if all other options have been exhausted.

Frequently Asked Questions

Q: Can I continue to drive my car if I see the check engine light with error code P261B?
A: It’s usually safe to drive your car with this error code, but you should take it to a mechanic as soon as possible.

Q: What are the signs and symptoms of a coolant pump malfunction?
A: The most common sign of a malfunctioning coolant pump is an overheated engine. You may also notice a decrease in engine performance and increased fuel consumption.

Q: How much does it cost to replace a coolant pump?
A: The cost of replacing a coolant pump varies depending on the make and model of your car. On average, the parts and labor for this repair can cost between $300 and $600.

Q: Can I replace the coolant pump myself?
A: While it is possible to replace the coolant pump yourself, this is a difficult job that requires a high level of technical knowledge and expertise. Unless you are an experienced mechanic, it is best to leave this job to the professionals.

Q: How long does it take to fix OBD-II Code P261B?
A: Depending on the cause of the error code, it can take anywhere from a few minutes to several hours to fix. In some cases, the repair may require multiple visits to the mechanic.


OBD-II Code P261B – Coolant Pump B Control Circuit Performance/Stuck Off is a common error code that can be caused by several issues ranging from a faulty coolant pump to a malfunctioning ECM. While it can be frustrating to see the check engine light, diagnosing and repairing this error code is relatively simple and can be done with the help of a skilled mechanic. I hope this article has provided you with a better understanding of what this error code means and how to fix it.

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