P0DD2: Hybrid/EV Battery Cell Balancing Circuit J Stuck Off

What does P0DD2 mean?

P0DD2 marks circuit J as unable to bleed: balancing is commanded, but the six cells of group J keep their charge. Ford lists the code in its 2015 hybrid OBD summary with the same power-up test as for the stuck-on case, run for 100 ms with the contactors still open, two consecutive power cycles and the 75 mV limit against the average cell voltage. GM's 2013 eAssist table documents a more direct test under its own code P1EAA: with the key off and the contactors open, a cell's balancing resistor is switched on and the cell voltage has to move by at least 0.1 V; two failed samples across key cycles give a Type A fault. Over many charges group J ends up high and caps the full charge. Opposite: P0DD1.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine light without noticeable change in driving
• Cells of group J at the top of the cell list at the end of charging
• Usable battery capacity declining over time

Common causes

• High Bleed resistor of circuit J open or burnt
• Medium Balancing switch of group J no longer closing
• Low Interrupted balancing lead between cell tap and board

Likelihood is a general estimate across vehicles; your make and model may differ.