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P2CA4

Particulate Filter Pressure Sensor Signals Swapped A/B

The ECM detects that the particulate filter pressure sensor signals A and B are reversed - low-pressure side reads as high-pressure side and vice versa. Most likely a wiring swap during service.

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

Symptoms

  • Check engine light or DPF warning light on
  • Power loss / limp mode
  • Increased fuel consumption
  • Failed forced regeneration attempts

Common causes

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

  • Sensor connectors A and B swapped during serviceCommon
  • Sensors installed in wrong positionsPossible

Parts involved

  • Pf Pressure Sensor A
  • Pf Pressure Sensor B
  • Wiring Harness

P2CA4 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.