Powertrain, generic · Hybrid propulsion

P0DD6 Hybrid/EV Battery Cell Balancing Circuit K Stuck Off

Check engine lightOn

EmissionsRelevant

Drive cycleRequired

Limp modeNo

P0DD6: group K's bleed path stays dead when balancing is called for. Ford includes it in its 2017 hybrid OBD summary; the BECM decides at power-up with open contactors, within 100 ms and over two power cycles, using the 75 mV deviation of one of the six cells from the average. LG's patent US20110285539A1 offers a direct check of the path: a sampling capacitor first takes on the cell's voltage and is then emptied through the balancing circuit; whatever voltage is left over must be close to zero, otherwise the circuit is faulty. Because nothing is drained, the car drives normally, but group K keeps reaching full charge first and the pack loses usable capacity. The stuck-on counterpart is P0DD5.

Likely causes

Open bleed resistor in circuit K

Balancing switch of group K failing to turn on

Cracked solder joint in the balancing path of K

Symptoms

Check engine light while the car drives normally
Group K highest at the end of charging
Electric range decreasing over many charges

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 kbms

References: law.cornell.edu, fordservicecontent.com, patents.google.com.