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DTC codes / P26xx · Computer and output circuits / P2670

P2670Actuator Supply Voltage 'B' Circuit Low

P2670 indicates that the powertrain control module (PCM) has detected a low voltage condition on the power supply circuit for an actuator, designated as circuit 'B'. The PCM monitors the voltage feed to this actuator and sets the code when the voltage falls below a calibrated threshold, typically because of a short to ground, high resistance, or a faulty actuator.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaComputer and output circuits

Symptoms you may notice

  • Illumination of the check engine light (malfunction indicator lamp).
  • Often no symptoms besides the warning light, especially if the actuator is not critical to engine operation.
  • The affected actuator may not function, leading to a loss of the system it controls (e.g., variable valve timing, turbo boost, or intake manifold tuning).
  • Reduced engine performance, such as poor acceleration or decreased fuel economy, if the actuator is part of the engine management system.
  • In some cases, the vehicle may enter limp mode or exhibit rough running if the actuator is essential for proper air/fuel management.

Common causes, most likely first

  1. A short to ground in the actuator supply voltage circuit 'B' wiring or connector.
  2. High resistance or an open in the power supply circuit, such as a corroded connector or damaged wire.
  3. A faulty actuator solenoid or motor that draws excessive current or has an internal short.
  4. A blown fuse or a faulty relay that supplies power to the actuator circuit.
  5. Poor ground connection for the actuator or the PCM, causing voltage drop.
  6. A malfunctioning PCM driver circuit, though this is less common.

How to diagnose and fix it

  1. Verify the code with a scan tool and check for any related codes or freeze-frame data to understand the conditions when the fault set.
  2. Inspect the wiring harness and connectors for the actuator supply circuit 'B' for signs of damage, corrosion, or loose pins.
  3. Check the fuse and relay that provide power to the actuator circuit; replace if blown or faulty.
  4. Measure voltage at the actuator connector with the key on, engine off; compare to battery voltage to identify excessive drop.
  5. Perform a resistance test on the actuator solenoid or motor to check for an internal short or open circuit.
  6. If voltage is low, trace the circuit back to the power source, checking for shorts to ground or high resistance; repair as needed.
  7. Clear the code and test-drive the vehicle to confirm the repair; if the code returns, further diagnose the PCM and its connections.

Common Missteps When Diagnosing P2670

  • A low voltage code for an actuator supply circuit often results from a simple blown fuse that protects multiple actuators, so always check fuses before condemning the actuator itself.
  • The actuator may be tested as faulty when the real problem is a corroded ground connection that affects the voltage supply to the actuator and other components on the same circuit.
  • In some vehicles, the actuator supply voltage 'B' circuit is shared with other sensors or actuators, so a fault in one component can cause a low voltage condition that sets P2670 without the actuator itself being defective.
  • A weak battery or charging system issue can cause a low voltage condition that triggers P2670, especially if the code sets during engine cranking or low idle.
  • Always refer to the vehicle-specific service information for the exact circuit and actuator affected, as the designation 'B' can vary between manufacturers and systems.

Can I keep driving with P2670?

If the check engine light is on but the vehicle runs normally, you can drive cautiously to a repair shop, but avoid heavy loads or aggressive driving. If the vehicle exhibits performance issues or enters limp mode, limit driving to essential trips and have it diagnosed promptly to prevent further damage.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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