DTC P0037-00: Ho2S Heater Control Circuit Low Input: Notes

DTC P0037:00 DETECTION CONDITION AND POSSIBLE CAUSE

DTC P0037:00	HO2S heater control circuit low input
DETECTION CONDITION	The PCM monitors the HO2S heater output voltage. If the PCM turns the HO2S heater off but the HO2S heater circuit remains low voltage, the PCM determines that the HO2S heater circuit has a malfunction. Diagnostic support note This is a continuous monitor (A/F sensor heater, HO2S heater). 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	Stops the fuel feedback control of the HO2S.
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 ENG2 15 A fuse and HO2S terminal C ENG2 15 A fuse malfunction Open circuit in wiring harness between ignition switch and HO2S terminal C Short to ground in wiring harness between HO2S terminal D and PCM terminal 2B PCM connector or terminals malfunction Open circuit in wiring harness between HO2S terminal D and PCM terminal 2B PCM malfunction
Courtesy of MAZDA MOTORS CORP.