P2671 OBD-II Trouble Code: Actuator Supply Voltage B Circuit High

P2671 Trouble Code definition

A P2671 code indicates a fault in the B circuit’s actuator supply, detected by the PCM or another control module, such as:

• body control module
• alternative fuel control module
• antilock brake control module
• instrument panel control module
• fuel injection control module
• anti-theft module
• cruise control module
• traction control module
• proximity alert module
• climate control module

What a P2671 Code Means

An actuator supply voltage B malfunction means a trouble code has been stored and a Malfunction Indicator Lamp (MIL) or Check Engine Light may be illuminated. This code applies to all manufacturers. Sometimes, multiple drive cycles may be needed for the MIL to illuminate.

Causes of P2671 Code

A P2671 code is often caused by :

• Shorted or open wiring or connectors between related control modules
• Shorted or open wiring or connectors in PCM input circuits from engine sensors
• Loose or disconnected ground wires to PCM or other control modules
• Internal malfunctions in PCM

Symptoms of P2671 Code

• Illuminated MIL or Check Engine Light
• Hard code stored
• Hard start/no start
• Rough running condition
• Engine misfire
• Poor fuel economy
• Lack of power

Diagnosing a P2724 Code

The code is in reference to the actuator voltage signal from/to various engine control actuators(CAN). CAN is an abbreviation for ‘controller area network,” a communications bus between multiple microcomputers without a host computer being needed, a system designed specifically for automotive applications. The CAN bus is a network of wiring harnesses and connectors used to share information between automotive control modules, and controls practically every electronic function in the vehicle, along with the PCM.

• A specialized scanner such as Autohex or Tech II may prove more useful in tracking down the specific malfunction than using a code reader and ohmmeter.

• Use a memory saving device in case the PCM or other controllers lose memory and would require reprogramming

• Specialized CAN scanners are available for diagnostics, showing pin values and control module operation and conditions. These scanners can give accurate real-time information while the vehicle is being operated.

• Control module ground circuits will need to be tested for continuity with battery ground.

• Check for any loose or dangling ground cables, straps or wires for the engine or transmission, from any recent repair work.

• Look for corroded or loose electrical connectors that might cause a code to be stored due to increased circuit resistance. When you’ve narrowed it down, find a CAN bus system wiring diagram and use a volt ohmmeter to check continuity between connectors. Compare findings against manufacturer’s specs and repair open or shorted connections if needed.

Additional Considerations for P2671 Code

CAN systems are extremely complex, some with up to 18 separate control modules. All it can take is one misplaced probe to destroy expensive control modules and require a complete reprogramming of the vehicle. Due to the complexity of these systems, it’s advisable that repairs to correct a P2671 code be left to experienced, qualified techs with the proper tools for diagnosis and repair. Diagnosing and repairing a P2671 code with a digital volt-ohmmeter, for example, would require testing hundreds or thousands of individual circuits separately.

Need help with a P2671 code?

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