DTC P0037:00 [L5]: Notes

WARNING: This page is about a different car, the 2009 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.

DETECTION CONDITIONS & POSSIBLE CAUSES

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 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 the first drive cycle. FREEZE FRAME DATA is available. The DTC is stored in the PCM memory.
POSSIBLE CAUSE	Without Advanced Keyless Entry And Push Button Start System HO2S connector or terminal malfunction Short to ground in wiring harness between ignition switch terminal C and HO2S terminal C Open circuit in wiring harness between ignition switch terminal C and HO2S terminal C HO2S heater malfunction PCM connector or terminal malfunction Short to ground in wiring harness between HO2S terminal D and PCM terminal 2B Open circuit in wiring harness between HO2S terminal D and PCM terminal 2B PCM malfunction With Advanced Keyless Entry And Push Button Start System HO2S connector or terminal malfunction Short to ground in wiring harness between relay block terminal 1B and HO2S terminal C Open circuit in wiring harness between relay block terminal 1B and HO2S terminal C HO2S heater malfunction PCM connector or terminal malfunction Short to ground in wiring harness between HO2S terminal D and PCM terminal 2B Open circuit in wiring harness between HO2S terminal D and PCM terminal 2B PCM malfunction
Courtesy of MAZDA MOTORS CORP.

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 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 the first drive cycle.
FREEZE FRAME DATA is available.
The DTC is stored in the PCM memory.

POSSIBLE CAUSE

Without Advanced Keyless Entry And Push Button Start System

HO2S connector or terminal malfunction
Short to ground in wiring harness between ignition switch terminal C and HO2S terminal C
Open circuit in wiring harness between ignition switch terminal C and HO2S terminal C
HO2S heater malfunction
PCM connector or terminal malfunction
Short to ground in wiring harness between HO2S terminal D and PCM terminal 2B
Open circuit in wiring harness between HO2S terminal D and PCM terminal 2B
PCM malfunction

With Advanced Keyless Entry And Push Button Start System

HO2S connector or terminal malfunction
Short to ground in wiring harness between relay block terminal 1B and HO2S terminal C
Open circuit in wiring harness between relay block terminal 1B and HO2S terminal C
HO2S heater malfunction
PCM connector or terminal malfunction
Short to ground in wiring harness between HO2S terminal D and PCM terminal 2B
Open circuit in wiring harness between HO2S terminal D and PCM terminal 2B
PCM malfunction

Courtesy of MAZDA MOTORS CORP.