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P2491 Powertrain

EGR Cooler Bypass Control Circuit High Bank 2

Same as P245D on bank 2. EGR mixes inert exhaust into intake to lower combustion peak temperature — too little raises NOx, too much causes misfires and rough running.

Affected components

  • Egr cooler bypass valve b2

Common causes

  • High likelihood: Control line shorted to supply
  • Low likelihood: Connector pins corroded - high contact resistance
  • Low likelihood: Supply wire pinched against B+ source

Possible symptoms

  • Check engine light on
  • Pinging or knocking under load
  • Power loss and hesitation
  • Possible rough idle
  • Failed emissions inspection (NOx)

Diagnostic notes

  • The malfunction indicator lamp may illuminate
  • This code can affect emissions

Related codes

Sources

Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.

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