DTC P2243:00: Notes

DTC P2243:00	A/F sensor reference voltage circuit open
DETECTION CONDITION	The PCM monitors the A/F sensor signal voltage at the PCM terminal 2Z. If the either of the following condition is met, the PCM determines that the A/F sensor reference voltage circuit is open. The PCM terminal 2Z voltage is specified voltage or more for 30 s . The PCM detects the DTC P0134:00 while the pending code P2243:00 is stored. MONITORING CONDITIONS Drive Mode 03 (EGR System, A/F Sensor Heater, HO2S Heater, A/F Sensor, HO2S and TWC Repair Verification Drive Mode) Following conditions are met: Engine is running Battery voltage: 11-18 V A/F sensor element impedance: specified or more Diagnostic support note This is a continuous monitor (A/F sensor, HO2S). The check engine light 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.
FAIL-SAFE FUNCTION	Fixes the duty value of the A/F sensor heater. Stops the fuel feedback control.
POSSIBLE CAUSE	A/F sensor connector or terminals malfunction PCM connector or terminals malfunction Open circuit in wiring harness between A/F sensor terminal 1C and PCM terminal 2Z A/F sensor malfunction PCM malfunction
Courtesy of MAZDA MOTORS CORP.