Skip to content
Book on WhatsApp

P06A4

Sensor Reference Voltage D Circuit Low

Same as P0652 on reference rail D. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.

  • Check engine light: Yes
  • Emissions related: Yes
  • Repair difficulty: medium

Symptoms

  • Check engine light on
  • Possible limp mode or no-start
  • Multiple follow-up faults across modules
  • Reset/relearn may be needed after repair

Common causes

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

  • Reference rail shorted to groundCommon
  • Connector pins corroded - high contact resistanceLess likely
  • Harness chafing through insulationLess likely

Parts involved

  • Sensor Reference Voltage D

P06A4 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.