Except California Emission Regulation Applicable ATX Model: Notes

DTC P0038 DETECTION CONDITION AND POSSIBLE CAUSES

DTC P0038	Rear HO2S heater circuit high input
DETECTION CONDITION	The PCM monitors the rear HO2S heater output voltage. If the PCM turns the rear HO2S heater off or on but the rear HO2S heater circuit remains high voltage, the PCM determines that the rear HO2S heater circuit has malfunction. Diagnostic support note  This is a continuous monitor (HO2S heater). MIL illuminates if PCM detects above malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for the same malfunction has been stored in PCM. PENDING CODE is available if PCM detects the above malfunction condition during first drive cycle. FREEZE FRAME DATA is available. The DTC is stored in the PCM memory.
POSSIBLE CAUSE	Short to power supply in wiring harness between rear HO2S terminal D and PCM terminal 2BE Short circuit in rear HO2S or PCM Rear HO2S heater malfunction PCM malfunction
Courtesy of MAZDA MOTORS CORP.