P0DD9 code meaning
Hybrid/EV Battery Cell Balancing Circuit L Stuck On
Powertrain system Generic code P0Dxx codes Check engine light
What P0DD9 means
P0DD9: the balancing path of group L will not switch off. The 2018 edition of Ford's hybrid OBD summary contains the code; the BECM catches it at power-up with the contactors still open, in a 100 ms check that compares each of the six cells of circuit L with the average and fails above 75 mV, again over two power cycles. GM shows a different route in its 2013 eAssist table: code P1B33 compares the reported balancing switch status with the commanded one and fails after 7 of 10 samples, as a two-trip fault. A switch that reads on while it should be off is exactly what P0DD9 describes. While parked the group drains, and the warm resistor stresses the module. Inactive opposite: P0DDA.
P0DD9 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1.5 to 8 hours
- Clears after repairAfter a drive cycle
Symptoms of P0DD9
- Check engine light after switching on
- Group L lower than the others after standing
- Less electric range
Common causes of P0DD9
- Most likelyBalancing switch of group L shorted
- PossibleBalancing command for L not cleared by the monitoring electronics
- Less likelySwitch status feedback of channel L reporting on although the switch is open
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 lBms
What each part of P0DD9 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| D9 | The exact fault in that area. |
What to do next
- Note P0DD9 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 P0DD9
What does P0DD9 mean?
P0DD9 means "Hybrid/EV Battery Cell Balancing Circuit L Stuck On". P0DD9: the balancing path of group L will not switch off. It is a generic code, so it means the same on every make.
Is it safe to drive with P0DD9?
Drive gently and only to a workshop. With P0DD9 the car can go into limp mode (reduced power) to protect itself.
Will P0DD9 fail an emissions test?
Yes, it can. P0DD9 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 P0DD9 to fix?
Difficulty: workshop only. A typical repair takes 1.5 to 8 hours of work. This is a job for a workshop.
Will P0DD9 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.