Fault code P2686 – actuator supply voltage “C” circuit high

Fault code P2686 is called “Actuator Supply Voltage “C” Circuit High” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.

Technical description and explained code P2686

OBD-II fault code P2686 is a generic code that is defined as “high signal level in circuit “C” of the actuator supply voltage”. It is set when the control module detects a high signal level between two or more control modules.

Fault code P2686 – actuator supply voltage

The Engine Control Module (ECM) is responsible for monitoring and adjusting numerous sensors and actuators. It also ensures that all these components work smoothly in accordance with the required values.

This is done in order to ensure maximum economy and performance of your vehicle.

When the ECM detects an abnormal value in the actuator supply voltage circuit. It recognizes the abnormality by comparing the actual values to the desired values.

If they are outside the desired limits, the malfunction indicator lamp (MIL) lights up on the instrument panel and code P2686 is written to memory. The ECM must monitor this fault for several cycles before the MIL will illuminate.

The “C” designation refers to part of the CAN circuit (controller network), not to a specific circuit, wire, or part. Use the technical service information from the original equipment manufacturer for determination.

Symptoms of vehicle malfunctions

The main signal that an error P2686 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.

It can also be warning signs such as:

  1. The “Check engine” control lamp on the control panel will light up (the code will be memorized as a fault).
  2. Other related fault codes may also be present.
  3. The actual symptoms depend on where in the CAN system the malfunction has occurred.
  4. Poor gear shifting.
  5. Engine stalls or starts poorly.
  6. Reduced engine performance.
  7. General poor drivability.
  8. Increased fuel consumption.

Error P2686 indicates a communication failure in the CAN system, so drivability problems and other symptoms may occur. Depending on what the failure affects, the error may be moderate or severe.

Factors that can cause this error code

The error code P2686 can mean that one or more of the following problems have occurred:

  • Burned, damaged, shorted or corroded wiring or connectors.
  • Damage to electronic or electrical components due to power surges.
  • Low battery or system voltage.
  • Water entering control modules and wiring harnesses.
  • Faulty or defective sensors.
  • Failure of PCM or other control module.

How to fix or reset OBD-2 code P2686

Some suggested steps for troubleshooting and fix the error code P2686:

  1. Read all stored data and error codes with an OBD-II scan tool. To find out when and under what circumstances error P2686 appeared.
  2. Clear the error codes from the computer memory and test-drive the vehicle to find out if the fault appears again.
  3. Measure the battery voltage and compare the obtained value with the value specified in the manufacturer’s specifications.
  4. Check the continuity of electrical circuits and connections.
  5. Test the Control Module (PCM) operation following the vehicle manufacturer’s procedure.
  6. Clear the error code from the computer memory again, test drive the vehicle to determine if the problem has been resolved.

Diagnose and repair of problems

Diagnosing the code P2686 is not recommended without special knowledge, because the CAN bus consists of thousands of circuits that connect many control units. In addition, there are a large number of sensors that are connected to the PCM by several hundred more circuits.

Finding a broken circuit is a complex task, requiring a complete check of the entire wiring harness and individual testing of each wire.

If you are confident enough in your diagnostic abilities to diagnose this code, start the procedure by inspecting all visible wiring. Look for obvious signs of damage, such as fuses, scuffs and corrosion.

If defects are found, the best option is to replace the appropriate section of the wiring harness between the connectors. Replace the wiring as necessary, remove any codes and re-scan the system for returning codes.

Since all control units require a reliable ground connection to operate, carefully check all ground connections. Consult your owner’s manual to locate all grounding points on the vehicle, as well as the actual location of all control modules.

If the P2686 code persists after fixing visible wiring damage, the chances of successfully solving the problem are very slim. Therefore, it is better to send the vehicle for professional diagnosis and repair.

On which vehicles does this problem occur most frequently

Fault code P2686 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:

  • Chevrolet
  • Chrysler
  • Citroen
  • Dodge
  • Ford
  • Honda
  • Nissan
  • Peugeot
  • Toyota
  • MAZ

Fault code P2686 can sometimes be found with other errors. The most common are the following: P2669, P2670, P2671, P2684, P2685.


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