DTC P2251:00: Notes

• The PCM monitors the A/F sensor terminal F 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 F voltage is below the specified.
• The PCM detects the DTC P0134:00 while the pending code P2251:00 is stored.

• This is a continuous monitor (A/F sensor, HO2S).
• The MIL illuminates if PCM detects the above malfunctioning 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 PCM detects the above malfunction conditions during first drive cycle.
• FREEZE FRAME DATA (Mode 2)/Snapshot data is available.
• The DTC is stored in the PCM memory

• A/F sensor connector or terminals malfunction
• PCM connector or terminals malfunction
• Open circuit in wiring harness between A/F sensor terminal D and PCM terminal 2AC
• A/F sensor malfunction
• PCM malfunction