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P0A79

Drive Motor B Inverter Performance

The drive motor B inverter does not deliver the expected power conversion. Switching loss elevated, gate driver fault, or capacitor degraded.

  • Check engine light: Yes
  • Emissions related: No
  • Repair difficulty: hard

Symptoms

  • EV/hybrid system warning light on
  • Reduced motor power or torque
  • Possible limp mode or vehicle shutdown

Common causes

Ordered by how often each turns out to be the cause.

  • IGBT switching characteristic degradedCommon
  • DC-link capacitor agedPossible

Parts involved

  • Drive Motor B Inverter
  • Hybrid Control Module

P0A79 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.