P0681 DTC Code: Understanding, Causes, and Troubleshooting


When it comes to diagnosing and troubleshooting automotive issues, Diagnostic Trouble Codes (DTCs) play a crucial role. One such DTC is the P0681 code, which can appear on various makes and models of vehicles. In this comprehensive guide, we will delve into the details of the P0681 DTC code, its meaning, common causes, and potential solutions. So, let’s dive in!

Understanding the P0681 DTC Code

The P0681 DTC code refers to the ‘Powertrain Control Module (PCM)/Engine Control Module (ECM) Power Relay Control Circuit Open’ error. In simpler terms, it indicates an issue with the power relay control circuit that activates the PCM/ECM. The PCM/ECM is responsible for managing the operation of crucial components in the engine, such as fuel injection, ignition timing, and emissions control.

Common Causes of the P0681 DTC Code

Several factors can trigger the P0681 DTC code. Understanding these causes will help you diagnose and resolve the issue effectively. Here are some of the most common culprits:

  1. Faulty PCM/ECM Power Relay: A malfunctioning power relay can disrupt the supply of power to the PCM/ECM, leading to the P0681 code.

  2. Open or Short Circuit: Wiring problems, such as open or short circuits, can interrupt the power relay control circuit, triggering the P0681 DTC code.

  3. Corroded Electrical Connections: Over time, electrical connections may accumulate corrosion or dirt, resulting in poor conductivity and causing the P0681 code.

  4. Blown Fuse: A blown fuse in the PCM/ECM power relay circuit can lead to the activation of the P0681 DTC code.

Troubleshooting the P0681 DTC Code

Resolving the P0681 DTC code involves a systematic approach to identify and address the underlying issues. Here’s a step-by-step troubleshooting process to help you get your vehicle back on track:

  1. Check the Power Relay: Start by inspecting the power relay associated with the PCM/ECM. Ensure it is functioning correctly and delivering power as needed. Replace the relay if any abnormalities are detected.

  2. Inspect the Wiring: Carefully examine the wiring harness and connectors related to the power relay control circuit. Look for signs of damage, loose connections, or corrosion. Repair or replace any faulty wiring as necessary.

  3. Test the Fuse: Use a multimeter to test the fuse associated with the PCM/ECM power relay circuit. If the fuse is blown, replace it with a new one of the same rating. Make sure to address any underlying issues that caused the fuse to blow initially.

  4. Clear the DTC Code: Once you have resolved the underlying issue, clear the DTC code using an OBD-II scanner. This step ensures that the code is no longer active and helps verify that the problem is resolved.

Frequently Asked Questions (FAQs)

To provide a better understanding of the P0681 DTC code, here are some frequently asked questions along with their answers:

Q1: Can I continue driving my vehicle with the P0681 code active?

A1: It is not recommended to drive your vehicle with an active P0681 DTC code. The code indicates a potential issue with the PCM/ECM power relay control circuit, which can lead to engine performance problems or even vehicle stalling. It is advisable to address the problem promptly to avoid further damage.

Q2: Can a loose battery connection trigger the P0681 DTC code?

A2: While a loose battery connection can cause various electrical issues, it does not usually trigger the P0681 code directly. However, it is good practice to ensure all connections, including the battery terminals, are secure and free from corrosion to maintain optimal electrical performance.

Q3: Can a software update fix the P0681 code?

A3: In some cases, a software update provided by the vehicle manufacturer may address specific PCM/ECM-related issues, including the P0681 DTC code. It is recommended to consult with a qualified mechanic or contact the manufacturer’s customer support to determine if a software update is available for your vehicle.


The P0681 DTC code is an important diagnostic indicator that alerts you to potential issues with the PCM/ECM power relay control circuit. By understanding the common causes and following the troubleshooting steps outlined in this article, you can effectively diagnose and resolve the P0681 code. Remember, if you lack the necessary expertise or tools, it is always recommended to seek assistance from a certified mechanic to ensure a proper and accurate diagnosis.

About author


Meet Sam Mitchell, your experienced and reliable guide in the complex world of car fault codes. With a robust career spanning over 15 years as a professional car mechanic, John has the skills, knowledge, and practical experience to help you navigate car fault issues with confidence.


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