OBD-II code · Powertrain (generic)

P0B39 Motor Electronics Coolant Pump B Control Circuit Low

The motor electronics coolant pump B control circuit reports a control circuit low condition. Power electronics cooling cannot be commanded reliably on branch B.

Is it safe to drive with P0B39?

The car may go into limp mode (reduced power). Get it diagnosed before a long trip.

Common causes

  • Most likelyControl wire shorted to ground
  • PossibleInternal short in pump motor
  • Less likelyConnector pins corroded - high contact resistance

Repair at a glance

Difficulty
Hard
DIY friendly
Best left to a mechanic
Typical labour
2–7 h
Emissions test
Usually unaffected
Parts involved
Motor Electronics Coolant Pump B, Wiring Harness, Hybrid Control Module

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.