P2D77 code meaning
Battery Charger Control Module B Performance
What P2D77 means
P2D77 says the control electronics of charger B, a second on-board charger or charger stage, do not work as intended; faults of its processor are filed separately under P2D78. No manufacturer documents P2D77 publicly. The A-side twin P0D67 shows what such a check covers: Ford's 2014 hybrid OBD summary flags it during an active charge for internal faults that prevent charging, such as overvoltage in the low- or high-voltage section, a failed PFC stage or a broken high-voltage current sensor. On the 2022 Outlander PHEV, Mitsubishi watches the charger's internal 3.3, 6 and 12 V rails for 1 s and then stops charging. That a charger B exists is shown by Toyota's 6.6 kW RAV4 Prime charger, whose B stage has its own codes. Plug-in charging fails; driving continues.
P2D77 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyWorkshop only
- Typical labor1 to 5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2D77
- AC charging does not start or stops after a short time
- Charging fault message or warning in the instrument cluster
- Charging possible only at reduced power, if the other charger path still works
Common causes of P2D77
- Most likelyInternal power or control stage of charger B failed (unit replacement)
- PossibleInternal low-voltage supply rail of charger B out of tolerance
- Less likelyWeak 12 V supply or poor ground at the charger
- Less likelyCharger software fault, cured by an update where one exists
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Battery charger cm bOn board charger
What each part of P2D77 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 77 | The exact fault in that area. |
What to do next
- Note P2D77 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 P2D77
What does P2D77 mean?
P2D77 means "Battery Charger Control Module B Performance". P2D77 says the control electronics of charger B, a second on-board charger or charger stage, do not work as intended; faults of its processor are filed separately under P2D78. It is a generic code, so it means the same on every make.
Is it safe to drive with P2D77?
P2D77 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will P2D77 fail an emissions test?
P2D77 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 P2D77 to fix?
Difficulty: workshop only. A typical repair takes 1 to 5 hours of work. This is a job for a workshop.
Will P2D77 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.