Powertrain, generic (extended)

P2D78 Battery Charger Control Module B Processor Performance

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P2D78 points at the processor inside the control module of charger B: its self-tests of program or working memory have failed, so the module no longer trusts its own computations. All other functional faults of that module belong to P2D77. No manufacturer documents P2D78 publicly. The kind of test meant is visible in the A-side twin P0E5E, for which Mitsubishi's 2023 PHEV code table names two triggers in the charger controller: a failed CRC check of the ROM and a failed RAM write/read test. CARB requires plug-in hybrids to detect charger malfunctions that disable charging or reduce charging performance. A charger that cannot vouch for its processor will not switch grid power into the battery, so charging is refused. Reprogramming may clear a corrupted memory image; a hardware fault means a new charger.

Likely causes

Memory or processor hardware in the charger B control unit defective
Corrupted charger software, e.g. after an interrupted update
12 V supply dip while the charger boots

Symptoms

  • Plug-in charging is refused right after connecting
  • Charging system warning in the cluster

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–3,500
Time0.5–5 h

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

Parts involved

battery charger cm bon board charger

Related codes

P2D77P0E5EP0D67

References: law.cornell.edu, mitsubishitechinfo.com.