To fix the P0685 code, you need to check for shorts, bad terminals or connections, and repair them if necessary. Additionally, you may need to replace the powertrain control module relay and the under hood junction block (fuse box), as well as any faulty battery cables or connectors.
Fuse replacement may also be required. If you’re experiencing this specific problem, AutoZone suggests that it could be a faulty electronic control unit (ECU) or an open circuit in the ECU. It is recommended to consult a professional mechanic for their expertise with this issue.
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Understanding The P0685 Code
Understanding the P0685 Code:
What is the P0685 code?
When this code is stored in the powertrain control module (PCM), it means that a low or no-voltage condition has been detected in the circuit which supplies the power to the ECM. The ECM power relay, also known as the engine control module relay, is responsible for delivering power to the ECM, which controls various components in the engine. If the ignition key turns off, the switches within the PCM power relay will not receive battery power, resulting in improper vehicle operation.
Causes of the P0685 code:
| Causes |
|---|
| Shorts or bad terminals or connections |
| Powertrain control module relay replacement |
| Under hood junction block replacement (fuse box) |
| Bad Battery cables and/or connectors replacement |
| Fuse replacement |
Symptoms of the P0685 code:
- Vehicle not starting or difficulty in starting
- Poor engine performance
- Engine misfires
- Check Engine Light illuminated
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Diagnosing And Fixing The P0685 Code
You can start diagnosing the P0685 code by using an OBD-II scanner. This tool will read the error codes stored in your vehicle’s computer system and provide you with valuable information about the issue. It will help you identify whether the problem lies with the power relay or some other component.
If the OBD-II scanner indicates that the power relay is the culprit, you should proceed with checking and replacing it. The PCM power relay, also known as the ECM power relay, is responsible for transferring power to the ECM. If the switches within the relay do not receive battery power, your vehicle may not operate properly.
While the power relay is a common cause of the P0685 code, there could be other potential causes as well. These may include shorts or bad terminals/connections, bad battery cables/connectors, or fuse issues. It is important to thoroughly inspect and address these potential causes to ensure a complete fix.
Once you have diagnosed and fixed the underlying cause of the P0685 code, you can use the OBD-II scanner to clear the error code from your vehicle’s computer system. This will reset the system and allow you to verify if the issue has been resolved successfully.
Preventative Measures For The P0685 Code
| Preventative Measures for the P0685 Code |
| Regular maintenance and inspection |
| Checking and maintaining battery connections |
| Proper handling of electrical components |
In order to prevent the P0685 code from occurring, it is important to regularly maintain and inspect your vehicle. This includes checking and maintaining battery connections to ensure they are secure and free from corrosion. Proper handling of electrical components is also essential to prevent any damage or interruption in power. Following these preventative measures can help to avoid issues with the P0685 code and keep your vehicle running smoothly.
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Frequently Asked Questions For How To Fix P0685 Code
Can A Bad Battery Cause P0685?
Yes, a bad battery can cause P0685. When the ignition key turns off, the switches within the PCM power relay will not receive battery power, resulting in improper vehicle operation. It is recommended to check and potentially replace the battery if this code is present.
What Is A Pcm Power Relay?
A PCM power relay is a switch that transfers power to the engine control module (ECM). If the ignition key is turned off, the relay will not receive battery power, causing issues with the vehicle’s operation. It is important to address any problems with the PCM power relay for proper vehicle functionality.
How Do I Fix Code P0686?
To fix code P0686, check for shorts or bad terminals and repair them. Replace the powertrain control module relay or the under hood junction block (fuse box). Also, consider replacing bad battery cables and connectors, as well as any blown fuses.
What Does The Ecm Relay Do?
The ECM relay, or engine control module relay, is responsible for transferring power to the ECM. It allows the ECM to control and regulate various components of your vehicle’s engine. If the relay malfunctions, your vehicle may not operate properly.
Ensure proper functioning with relay replacement services.
Conclusion
To fix the P0685 code, it is crucial to address the power relay issue. The PCM power relay plays a crucial role in supplying power to the ECM, which controls the functioning of various components in the engine. If this relay fails to receive battery power, your vehicle may experience performance issues.
Therefore, it is recommended to check for shorts, bad terminals, or connections and replace the power relay if needed. Additionally, ensure that the battery cables and connectors are in good condition, and consider replacing any faulty fuses. By addressing these issues, you can ensure that your vehicle operates properly and efficiently.
