Powertrain, generic · Hybrid propulsion

P0D91 Battery Charger Coupler Lock Control Circuit/Open

Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P0D91 means the module that drives the charge-plug latch sees its lock output as electrically open: when it commands the latch closed, no current flows through the wiring and actuator winding. Without a confirmed lock, the car normally refuses to start a charging session, because the plug could be withdrawn under load. Mercedes-Benz documents P0D9100 in the drivetrain control unit (PTCU, N127) of its recent P3 plug-in hybrids such as the S 580 e and the AMG GT 63 S E and C 63 S E: bulletin LI47.70-P-078127 describes a car that will not charge on AC with the check engine light on and names hardware or software as possible causes still under investigation. Shorts on this output are P0D92/P0D93, a driven but ineffective lock is P0D94, and the release side has P0D95–P0D98.

Likely causes

Connector at the lock actuator loose, corroded or backed out
Broken wire in the harness between control unit and inlet
Motor winding inside the lock actuator burnt through
Driver stage or software of the controlling module (Mercedes names both)

Symptoms

  • Vehicle does not charge on AC
  • Check engine light on (Mercedes)
  • Charging system warning in the instrument cluster

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–600
Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

charge port lock actuatorwiring harnesson board charger

Related codes

P0D92P0D93P0D94P0D95P0D9E

References: static.nhtsa.gov, patents.google.com, law.cornell.edu.