P1680 DTC Code


In the world of automotive diagnostics, understanding and troubleshooting DTC codes is essential. One such code is the P1680 DTC code which indicates a problem related to the engine’s internal control module.

In this comprehensive guide, we will delve deep into the P1680 DTC code, its meaning, the underlying causes, possible symptoms, and the necessary steps to diagnose and fix the issue. So, buckle up and let’s explore this topic together!

Understanding the P1680 DTC Code

The P1680 DTC code, also known as “Driver 5 Line 0” or “EFI 5 volt reference circuit 1 open,” is a trouble code encountered in many vehicles, including cars, pickup trucks, and SUVs. This code indicates a malfunction within the engine’s internal control module, commonly referred to as the ECM.

Causes of the P1680 DTC Code

Several factors can contribute to the occurrence of the P1680 DTC code. Understanding these potential causes is essential for diagnosing and rectifying the issue. Let’s explore some common culprits:

  1. Faulty ECM Wiring: One possible cause of the P1680 DTC code is a wiring problem within the ECM circuit. This can include loose connections, damaged wiring, or short circuits.

  2. Defective ECM: Over time, an ECM may encounter internal failures, leading to the triggering of the P1680 code. These failures can result from age, heat, vibration, or electrical issues.

  3. Electrical Interference: External or internal sources of electrical interference can disrupt the ECM circuitry, causing the P1680 code to appear. These interferences may include faulty sensors, damaged wiring harnesses, or issues with other electronic components in the vehicle.

  4. Power Supply Issues: Insufficient or erratic power supply to the ECM can also lead to the P1680 DTC code. This may occur due to a faulty battery, alternator, or voltage regulator.

Symptoms of the P1680 DTC Code

Detecting symptoms associated with the P1680 DTC code can greatly aid in diagnosis. Here are some signs that may indicate the presence of this code:

  • Check Engine Light: The most obvious symptom is the illumination of the check engine light on the dashboard. This serves as an early warning that something is amiss within the engine control system.

  • Engine Performance Issues: A vehicle experiencing the P1680 DTC code may exhibit various performance problems. These can include rough idling, hesitations, or sluggish acceleration.

  • Stalling: In severe cases, the engine may stall intermittently or struggle to maintain a consistent idle speed.

  • Reduced Fuel Efficiency: You may notice that your vehicle is consuming more fuel than usual. This decrease in fuel efficiency can be attributed to the compromised engine control system.

How to Diagnose the P1680 DTC Code

Diagnosing the P1680 DTC code can be a complex task but following a systematic approach can simplify the process. Here’s a step-by-step guide:

  1. Scan for Other Codes: Begin by connecting an OBD-II scanner to your vehicle’s diagnostic port. Check if any other codes are present along with the P1680 code. These accompanying codes can provide additional clues about the underlying issue.

  2. Inspect the ECM Wiring: Thoroughly examine the ECM wiring harness for any visible signs of damage, such as frayed wires or loose connections. Repair or replace any faulty wiring as needed.

  3. Test the ECM Operation: Verify the functionality of the ECM by conducting output tests using a specialized diagnostic tool. This will help identify any internal ECM failures and confirm if the module requires replacement.

  4. Check for Electrical Interference: Inspect the surrounding electrical components and wiring harnesses for possible sources of electrical interference. Ensure proper grounding, and replace or repair any damaged or faulty components.

  5. Test the Power Supply: Measure the voltage output of the battery, alternator, and voltage regulator to rule out any power supply issues. Replace or repair any components found to be faulty.

  6. Clear the Code and Test Drive: Once you have addressed or repaired any detected faults, clear the P1680 DTC code using the OBD-II scanner. Take your vehicle for a test drive to ensure that the code does not reappear and that the symptoms have been resolved.

Frequently Asked Questions (FAQ)

  1. Q: Can I continue driving my vehicle with the P1680 DTC code? A: While it may be possible to drive the vehicle with the P1680 code, it is strongly recommended to address the issue as soon as possible. Ignoring the code can lead to further damage to the engine control system and potentially more severe problems.

  2. Q: Can a P1680 code be intermittent? A: Yes, the P1680 code can be intermittent, meaning it may appear and disappear sporadically. The intermittent nature of the code can make diagnosis more challenging, but it is still essential to identify and rectify the underlying problem.

  3. Q: Can a faulty sensor trigger the P1680 code? A: Yes, a faulty sensor within the engine control system can potentially trigger the P1680 DTC code. It is crucial to inspect all relevant sensors during the diagnostic process and replace any found to be defective.

To conclude, the P1680 DTC code is indicative of an issue within the engine control module of your vehicle. By understanding its causes, symptoms, and following a systematic diagnostic approach, you can successfully diagnose and rectify the problem. Remember to consult a certified automotive technician if you encounter any difficulties during the process for expert guidance and assistance. Safe driving!

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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