[SOLVED] P0685 Code: Fix Engine Control Module Power Relay Circuit Open!

Are you experiencing trouble with your car and wondering what the fault code P0685 means? Well, this code indicates a problem with the Engine Control Module (ECM) power relay.

The symptoms of this issue can vary, but one common symptom is a weak battery and low voltage while cranking. The causes of this fault code can include a faulty ECM power relay, an open or shorted ECM power relay harness, poor electrical connection in the ECM power relay circuit, a blown ECM fuse, or a faulty ECM itself.

To fix this problem, start by visually inspecting the wiring harness and connectors for any damage. Check for broken, bent, pushed out, or corroded pins in the connectors. This repair is of moderate importance and difficulty, with an estimated repair time of 1.0.

Don’t worry, you can easily interpret the fault code by checking the “Possible Causes” mentioned above.

Repair Importance Level10.0 (Out of 10)
Estimated Repair TimeApproximately 1.0 hour
Repair Difficulty Level10.0 (Out of 10)

Experiencing starting issues, engine misfires, and electrical malfunctions?

Check out the symptoms of fault code p0685 below.

  • The symptoms of the automobile fault code P0685 include: engine misfires, rough idling, stalling, difficulty starting the vehicle, reduced power and acceleration, illuminated check engine light, and potential loss of communication with the engine control module (ECM).

The automobile fault code p0685 can be caused by a weak battery, faulty ECM power relay, open or shorted harness, poor electrical connection, blown ECM fuse, or a faulty ECM.

  • The fault code P0685 can be caused by: weak battery with low voltage while cranking, faulty Engine Control Module (ECM) power relay, open or shorted ECM power relay harness, poor electrical connection in the ECM power relay circuit, blown ECM fuse, and a faulty ECM.

To fix the p0685 fault code, start by visually inspecting the wiring harness, connectors, and components for any damage or corrosion.

  • To fix the automobile fault code p0685, first, check the possible causes mentioned above.
  • Then, visually inspect the wiring harness and connectors related to the issue.
  • Look for any damaged components and check if there are any broken, bent, pushed out, or corroded pins in the connectors.
  • This fix is estimated to take approximately 1.0 hour.

The factors influencing the diagnosis and fixing cost of the automobile fault code p0685 are the estimated repair time of 1.0 hour and the average hourly rate charged by auto repair shops, which ranges between $75 and $150.

When you see the Engine Light ON or the Service Engine Soon Warning Light, it could be due to the fault code P0685. This code indicates a problem with the ECMPCM Power Relay Control Circuit.

In simpler terms, it means that there is an issue with the power supply to the engine control module or powertrain control module. The ECMPCM is responsible for controlling various functions of your vehicle’s engine, such as fuel injection, ignition timing, and emissions. When the power relay control circuit malfunctions, it can disrupt the communication between the ECMPCM and other components, leading to performance issues and potential engine problems. To fix this issue, you will need to diagnose the exact cause of the power relay control circuit malfunction.

It could be a faulty relay, a wiring issue, or a problem with the ECMPCM itself. It is recommended to seek the assistance of a qualified mechanic or use a diagnostic tool to pinpoint the exact cause.

Once identified, the faulty component can be repaired or replaced to restore proper functioning of the ECMPCM and clear the fault code. Remember, addressing this issue promptly can prevent further damage to your vehicle’s engine and ensure optimal performance.

What are the possible causes of the automobile fault code P0685?

The fault code P0685 in an automobile can be caused by various factors. One possible cause is a weak battery, resulting in low voltage while cranking. Another potential cause is a faulty Engine Control Module (ECM) power relay or an open or shorted ECM power relay harness. Poor electrical connection in the ECM power relay circuit or a blown ECM fuse can also trigger this fault code. To fix the issue, it is recommended to check the possible causes mentioned above. Additionally, visually inspect the wiring harness and connectors for any damage, and look out for broken, bent, pushed out, or corroded pins in the connectors.

How can I visually inspect the wiring harness and connectors to fix the fault code P0685?

To fix fault code P0685, start by visually inspecting the wiring harness and connectors. Look for any damaged components and check if there are any broken, bent, pushed out, or corroded pins in the connectors. This can help identify any issues with the weak battery, low voltage while cranking, faulty ECM power relay, open or shorted ECM power relay harness, poor electrical connection in the ECM power relay circuit, blown ECM fuse, or a faulty ECM. Take note of the possible causes mentioned and thoroughly examine the wiring and connectors for any signs of damage or poor connections.

What should I look for when checking for damaged components and connector’s pins to resolve the fault code P0685?

To resolve the fault code P0685, start by visually inspecting the wiring harness and connectors. Look for any damaged components and check for broken, bent, pushed out, or corroded connector’s pins. This can help identify any issues with the weak battery, low voltage while cranking, faulty ECM power relay, open or shorted ECM power relay harness, poor electrical connection in the ECM power relay circuit, blown ECM fuse, or a faulty ECM. Be thorough in your inspection to ensure a proper fix.

p0685 error fault code explained

If you’re experiencing weak battery or low voltage while cranking, it could be due to a faulty Engine Control Module (ECM) power relay or issues with the ECM power relay harness.

To fix this, visually inspect the wiring harness and connectors for any damage, and check for broken or corroded pins.

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