P0DC9Hybrid/EV Battery Cell Balancing Circuit H Stuck On
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- P0DC9: the bleed path of group H keeps conducting. Ford lists the code for its 2016 hybrid and plug-in BECM, judged at start-up from the cell spread within the six-cell circuit. Besides draining charge, a switch that cannot open turns energy into heat around the clock. Monitoring chips are built to limit that heat: TI's BQ79616-Q1 pauses all balancing when sensors next to its internal bleed FETs exceed about 105 °C, or when a thermistor near the external resistors passes a set limit. A shorted FET ignores such a pause, so the hot spot persists. Expect group H to sit low after standstill. The CARB rule permits judging balancing by switch response. Circuit fault: P0DC8, inactive case: P0DCA.
- What you may notice
- Check engine light and hybrid battery warning
- Group H noticeably lower than the rest after parking
- Locally raised temperature reading in the battery module
- Likely causes
- LikelyBleed FET of group H shorted and unaffected by thermal pause
- PossibleHeat damage on the monitoring board around the bleed resistors of H
- RareChip logic keeping the balancing enable of channel H active
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €300 – €4,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.