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P2378

Turbocharger Inlet Pressure Sensor B Circuit Intermittent or Erratic

Same as P2374 but the signal is intermittent or has spikes that the ECU cannot reconcile - typically a wiring or connector fault.

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

Symptoms

  • Check engine light on
  • Significant power loss / limp mode
  • Possible blue or black smoke from exhaust
  • Whistling or hissing sound from intake

Common causes

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

  • Intermittent contact at connector or terminalCommon
  • Harness chafed or pinchedPossible
  • Connector with intermittent contact under vibrationLess likely

Parts involved

  • Turbo Inlet Pressure Sensor B
  • Turbo Inlet Pressure Wiring B

P2378 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.