P2D79 code meaning
Charging Stop Switch Circuit
What P2D79 means
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.
P2D79 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2D79
- Charging cannot be ended with the stop button
- Charging may be refused as a precaution
Common causes of P2D79
- Most likelyLoose, corroded or unplugged connector at the stop switch
- PossibleBroken wire between stop switch and charging control unit
- PossibleStop switch itself defective
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Charging stop switchWiring harness
What each part of P2D79 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 79 | The exact fault in that area. |
What to do next
- Note P2D79 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2D79
What does P2D79 mean?
P2D79 means "Charging Stop Switch Circuit". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P2D79?
P2D79 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will P2D79 fail an emissions test?
P2D79 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is P2D79 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. This is a job for a workshop.
Will P2D79 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.