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P2049

Reductant Injection Valve Circuit High (Bank 1 Unit 1)

Reductant Injection Valve Circuit High (Bank 1 Unit 1): the signal voltage is above the expected range. This valve doses reductant (DEF/AdBlue) into the exhaust for SCR NOx reduction.

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

Symptoms

  • Check engine light or NOx warning on
  • AdBlue/DEF level or quality warning
  • Possible no-start countdown after ignore period
  • Failed emissions inspection (NOx)

Common causes

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

  • Short to B+Common
  • Connector pins corroded - high contact resistanceLess likely
  • Supply wire pinched against B+ sourceLess likely

Parts involved

  • Reductant Injection Valve

P2049 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.