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P26D0

Engine Coolant Pump Control Module System Voltage Low

The smart coolant pump module reports the system voltage below operating range. Pump output is reduced or disabled to protect the module.

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

Common causes

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

  • Weak battery sags voltage under loadCommon
  • Alternator output below regulation pointPossible

Parts involved

  • Smart Coolant Pump Module
  • Charging System
  • Battery

P26D0 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.