Powertrain, generic · Hybrid propulsion

P0DC9 Hybrid/EV Battery Cell Balancing Circuit H Stuck On

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

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.

Likely causes

Bleed FET of group H shorted and unaffected by thermal pause
Heat damage on the monitoring board around the bleed resistors of H
Chip logic keeping the balancing enable of channel H active

Symptoms

  • Check engine light and hybrid battery warning
  • Group H noticeably lower than the rest after parking
  • Locally raised temperature reading in the battery module

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€300–4,500
Time1.5–8 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

hv battery cell balancing circuit hbms

Related codes

P0DABP0DC8P0DCAP0DCBP0DC5P0DE6

References: law.cornell.edu, fordservicecontent.com, ti.com.