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DTC codes / P0Dxx · Hybrid propulsion / P0D91

P0D91Battery Charger Coupler Lock Control Circuit/Open

P0D91 indicates that the battery charger coupler lock control circuit is open, meaning the powertrain control module (PCM) has detected an interruption in the electrical path that commands the locking mechanism for the charging coupler. This circuit is used on plug-in hybrid and electric vehicles to secure the charge connector during charging, and an open circuit prevents the lock from engaging or disengaging as intended.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaHybrid propulsion

Symptoms you may notice

  • The charge coupler may fail to lock onto the vehicle inlet, allowing it to be removed during charging.
  • A warning light on the instrument cluster, often accompanied by a message to check the charging system.
  • The vehicle may refuse to start or may not allow charging to begin if the lock is not confirmed.
  • In some cases, the lock may remain engaged and prevent removal of the charging connector.
  • Often no symptoms besides the warning light, especially if the fault is intermittent or only affects the lock confirmation signal.

Common causes, most likely first

  1. A broken or corroded wire in the coupler lock actuator circuit, commonly at the connector or where the harness flexes near the charge port.
  2. A failed coupler lock actuator solenoid or motor that has an open winding.
  3. A poor electrical connection at the lock actuator connector, such as backed-out pins or water intrusion.
  4. An open circuit inside the charge port assembly due to damage or wear.
  5. A faulty PCM or control module driver for the lock circuit, though this is less common.
  6. Rodent damage or physical damage to the wiring harness between the control module and the charge port.

How to diagnose and fix it

  1. Perform a visual inspection of the charge port area and the coupler lock actuator for obvious damage, corrosion, or disconnected connectors.
  2. Use a scan tool to command the coupler lock on and off while listening for actuator operation and checking for related diagnostic trouble codes (DTCs).
  3. Disconnect the lock actuator connector and measure resistance across the actuator terminals to check for an open winding; compare to specification.
  4. Check for continuity and voltage on the control circuit from the PCM to the actuator connector while commanding the lock, looking for an open or short.
  5. Inspect the wiring harness along its routing for chafing, breaks, or rodent damage, and repair as needed.
  6. If the actuator tests good but the circuit is open, trace the circuit to the PCM and check for a faulty PCM driver or internal open.
  7. Replace the faulty coupler lock actuator or repair the wiring, clear the codes, and verify the lock operates correctly with a scan tool.

Don't overlook the charge port harness

  • The coupler lock actuator is often integrated into the charge port assembly, so a failed actuator may require replacing the entire port rather than a separate component.
  • An open circuit can be caused by a poor ground connection for the lock actuator, which is easy to miss when focusing only on the power side of the circuit.
  • Intermittent opens often occur where the harness flexes near the charge door hinge, so wiggle-testing the harness while monitoring the circuit can reveal the fault.
  • A scan tool that can read live data for the coupler lock status is essential; a simple code reader may not show the actual lock command or feedback.
  • This code does not always mean the actuator is defective; a loose connector or chafed wire is a more frequent cause of an open circuit.

Can I keep driving with P0D91?

You can generally drive the vehicle, but charging may be disabled or unreliable, and the connector may not lock securely. Avoid leaving the vehicle plugged in unattended if the lock does not engage, and have the fault diagnosed soon to prevent charging interruptions.

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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