Technical Description of OBD-II Trouble Code
The Actuator Supply Voltage B Circuit is registering a high voltage.
What does that mean?
This is a generic diagnostic trouble code (DTC) that applies to OBD-II vehicles. It can be found in various vehicle makes such as Dodge, Chrysler, Ford, Chevrolet, Toyota, Honda, Nissan, etc.
The Engine Control Module (ECM) is responsible for monitoring and adjusting sensors, solenoids, actuators, valves, etc. It ensures that all these components are working together to achieve optimal vehicle performance and fuel efficiency. If you receive a P2671 or a related code, depending on your vehicle make and model, you may experience transmission drivability issues.
It’s worth noting that in my experience with European models, this code can also be related to an EVAP diagnostic issue. Therefore, it is important to consult your service manual for accurate diagnostic guidance. Often, your symptoms will provide clues about the systems/components involved in the fault.
Regarding the P2671 code and related codes, the ECM detects an abnormal value in the actuator supply voltage circuit. It compares the actual values to the desired ones and if they deviate beyond a certain range, the Malfunction Indicator Lamp (MIL) on your instrument panel will illuminate. The ECM must monitor this fault over multiple drive cycles before activating the MIL. It is crucial to research the designation for “B” within the circuit, as it may refer to a specific wire, harness, or location. Always consult the OEM technical service information for accurate guidance.
Depending on your vehicle’s make and model, the Transmission Control Module (TCM) may also detect this code with a different description.
P2671 (Actuator Supply Voltage B Circuit High) is active when the ECM or TCM detects a high voltage condition in the actuator supply voltage “B” circuit.
What is the severity of this DTC?
Generally speaking, the severity of this DTC is moderate. However, since there are multiple code descriptions, caution should be exercised during diagnosis. Proper service data is necessary. If this code pertains to the transmission in your case, it is advisable to address the issue promptly. Continuing to use a vehicle with an active transmission code poses a risk that should be avoided.
What are some of the symptoms of the code?
Symptoms associated with a P2671 diagnostic code may include:
What are some of the common causes of the code?
Possible causes for the P2671 trouble code include:
What are some P2671 diagnostic and troubleshooting steps?
The initial step in troubleshooting any malfunction is to research the Technical Service Bulletins (TSB) for known issues specific to your vehicle.
Advanced diagnostic steps are highly vehicle-specific and may require specialized equipment and knowledge for accurate execution. Below are basic steps, but refer to a vehicle-specific repair guide for detailed instructions.
Basic Step #1
The approach to diagnosing this code depends on your vehicle’s make, model, and symptoms. Generally, start by clearing the codes with a scanner and driving the vehicle until the code becomes active again. Once you identify the correct circuit/harness, inspect it for any damage. The circuit may be located under the vehicle, making it susceptible to damage from road debris, dirt, or ice. Repair any open or chafed wires if found. Additionally, inspect the connectors involved. Disconnect them to check for bent or damaged pins that could cause electrical issues. Sometimes, high resistance within a circuit can generate excessive heat, leading to insulation damage. This would indicate the source of the problem.
NOTE: Always solder and shrink-wrap any damaged wires, especially when exposed to the elements. Replace connectors with OEM ones to ensure proper electrical connections.
Basic Step #2
Refer to your service information to locate the actuator. In some cases, the actuator may be externally accessible. If so, verify its integrity using a multimeter and the service manual. The desired values for this test vary significantly, so ensure you have the necessary tools and information. If the recorded values deviate from the desired range, the sensor may be defective and should be replaced with a new one.
Basic Step #3
Inspect the Engine Control Module (ECM) and Transmission Control Module (TCM) for any visible damage. Sometimes, these modules are located in areas prone to water accumulation, leading to corrosion. The presence of green powder should raise concerns. Given the complexities of ECM diagnosis, a licensed technician should handle this stage.
This article is intended for informational purposes only, and the technical data and service bulletins specific to your vehicle should always take precedence.
