P0DDE: Hybrid/EV Battery Cell Balancing Circuit M Stuck Off

What does P0DDE mean?

P0DDE means group M is not bled when it should be. Ford carries the code in its 2016 hybrid OBD summary with the usual BECM start-up rule: 100 ms with open contactors, six cells per circuit, a 75 mV gap to the average, confirmed over two power cycles. A balancing channel can also be stopped on purpose, which a diagnosis must keep apart from a real failure. TI's BQ79616-Q1 data sheet lists such ends: the per-channel timer expires, the cell falls below a set voltage, an unmasked fault appears or the host stops balancing. Only a path that never conducts after a valid start counts here. Left alone, the fuller cells of M reach their limit first at every charge, and the pack gives away capacity. Stuck-on case: P0DDD.

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

Symptoms

• Check engine light while driving feels normal
• Group M highest at the end of each charge
• Less usable battery energy over time

Common causes

• High Bleed resistor of circuit M open
• Medium Balancing switch of group M that no longer turns on
• Low Intended balancing stop for M misjudged as no response by the software

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