Powertrain, generic (extended)

P2D79 Charging Stop Switch Circuit

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P2D79 covers the circuit of a charging stop switch as a whole, a button the driver presses to end external charging before the battery is full. The code is set when the switch line carries no valid signal at all; high, low, performance and intermittent faults of the same line have their own codes P2D7A to P2D7D. No manufacturer documents P2D79 publicly. The part itself is described in patents: in Toyota's design the charging ECU receives a stop signal for as long as the button is held, and Honda's older EV charger ran until the battery was full or its stop switch was turned on. Under CARB, hybrid parts a maker chooses to monitor are judged like any other input, circuit faults included. With an unreadable stop button, the car may refuse to charge or may simply ignore the button.

Likely causes

Loose, corroded or unplugged connector at the stop switch
Broken wire between stop switch and charging control unit
Stop switch itself defective

Symptoms

  • Charging cannot be ended with the stop button
  • Charging may be refused as a precaution

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–400
Time0.5–2.5 h

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

Parts involved

charging stop switchwiring harness

Related codes

P2D7AP2D7BP2D7CP2D7DP2D7E

References: law.cornell.edu, patents.google.com, patents.google.com.