P0DB1 code meaning
Hybrid/EV Battery Cell Balancing Circuit B Stuck On
Powertrain system Generic code P0Dxx codes Check engine light
What P0DB1 means
P0DB1: in circuit B the bleed path stays closed even after the controller withdrew the command. The cells of group B are drained without pause, so their voltage falls behind the others, worst during long standstill. Detection usually compares commanded and reported switch state; GM's eAssist logic for a related code needs 7 failed of 10 samples before a Type B entry. Toshiba describes a comparator check that spots a shorted balancing switch while it should be off. Ford names P0DB1 for its hybrid BECM; the 2015 OBD summary flags it when, at start-up with open contactors, one of the six cells served by circuit B differs from the pack mean by more than 75 mV. The electrical fault of the same circuit is P0DB0, the opposite stuck state P0DB2.
P0DB1 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor2 to 8 hours
- Clears after repairAfter a drive cycle
Symptoms of P0DB1
- MIL with battery warning
- Group B cells clearly low after parking
- Usable charge and range shrinking
Common causes of P0DB1
- Most likelyShorted balancing transistor in circuit B
- PossibleDrive output of the monitoring chip stuck active
- Less likelyMoisture or contamination on the module board creating a leakage path
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hv battery cell balancing circuit bBms
What each part of P0DB1 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| B1 | The exact fault in that area. |
What to do next
- Note P0DB1 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 P0DB1
What does P0DB1 mean?
P0DB1 means "Hybrid/EV Battery Cell Balancing Circuit B Stuck On". P0DB1: in circuit B the bleed path stays closed even after the controller withdrew the command. It is a generic code, so it means the same on every make.
Is it safe to drive with P0DB1?
Drive gently and only to a workshop. With P0DB1 the car can go into limp mode (reduced power) to protect itself.
Will P0DB1 fail an emissions test?
Yes, it can. P0DB1 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0DB1 to fix?
Difficulty: workshop only. A typical repair takes 2 to 8 hours of work. This is a job for a workshop.
Will P0DB1 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.