DTC P0054:00: Notes

DTC P0054:00	HO2S heater resistance problem
DETECTION CONDITION	The PCM monitors the HO2S heater resistance when under the HO2S heater control. If the resistance is more than 51 ohms  , the PCM determines that there is a HO2S heater circuit problem. Diagnostic support note  This is an intermittent monitor (A/F sensor heater, HO2S heater). 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	HO2S connector or terminals malfunction HO2S heater malfunction Short to ground or open circuit in HO2S heater power supply circuit Short to ground in wiring harness between ignition switch*1 /relay block*2 and HO2S terminal C ENG 20 A fuse malfunction Open circuit in wiring harness between ignition switch*1 /relay block*2 and HO2S terminal C Short to ground in wiring harness between HO2S terminal D and PCM terminal 2D PCM connector or terminals malfunction Open circuit in wiring harness between HO2S terminal D and PCM terminal 2D PCM malfunction
Courtesy of MAZDA MOTORS CORP.

^*1 : Vehicles without advanced keyless entry and push button start system

^*2 : Vehicles with advanced keyless entry and push button start system