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P2D59

Generator B Over Temperature

Generator B reports temperature above the protection threshold. Sustained high load or cooling path obstruction.

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

Common causes

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

  • Sustained high generator loadCommon
  • Cooling path blockedPossible

Parts involved

  • Generator B
  • Wiring Harness
  • ECM

P2D59 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.