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DTC P2251:00: Notes

DTC P2251:00 (L3 WITH TC) DETECTION CONDITION & POSSIBLE CAUSES

DTC P2251:00 A/F sensor negative current control circuit open
DETECTION CONDITION 
  • The PCM monitors the A/F sensor terminal 1C voltage. If either of the following conditions are met, the PCM determines that the A/F sensor negative current control circuit is open.

MONITORING CONDITIONS 
  • The A/F sensor element impedance specified or more.
  • Circuit voltage oscillation or A/F sensor terminal 1C voltage is below the specified.
  • The PCM detects the DTC P0134:00 while the pending code P2251:00 is stored.

Diagnostic support note 
  • This is a continuous monitor (A/F sensor, HO2S).
  • The MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.
  • PENDING CODE is available if the PCM detects the above malfunction condition during first drive cycle.
  • FREEZE FRAME DATA (Mode 2)/Snapshot data is available.
  • The DTC is stored in the PCM memory.
POSSIBLE CAUSE 
  • A/F sensor connector or terminals malfunction
  • PCM connector or terminals malfunction
  • Open circuit in wiring harness between A/F sensor terminal 1B and PCM terminal 2AC
  • A/F sensor malfunction
    • A/F sensor heater cannot be controlled.
  • PCM malfunction
G06731689Courtesy of MAZDA MOTORS CORP.
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