DTC P0037: Ho2S Heater Control Circuit Low (Bank 1 Sensor 2)

OUTLINE OF DIAGNOSIS
Detect the open or short circuit of rear oxygen sensor heater.

Judge NG when out of the standard value.
COMPONENT DESCRIPTION

Fig 1: Heated Oxygen Sensor Cross Sectional View - Bank 1 Sensor 2
Courtesy of SUBARU OF AMERICA, INC.

ENABLE CONDITION

ENABLE CONDITIONS

Secondary Parameters	Enable Conditions
Ignition switch	ON
Engine speed	"GREATER THAN EQUAL TO" 500 rpm
After engine starting	10 seconds or more
Battery voltage	"GREATER THAN EQUAL TO" 8 V

GENERAL DRIVING CYCLE
In 10 seconds after starting the engine, perform the diagnosis just once.

DIAGNOSTIC METHOD

Judge NG when the continuous time until completing the malfunction criteria below becomes 10 seconds or more. Judge OK when the continuous time until completing none of the malfunction criteria below becomes 10 seconds or more.

Judgment Value

JUDGMENT VALUE

Malfunction Criteria	Threshold Value
Calculated electric power	< 6 watts

Time needed for diagnosis: 10 seconds

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

DTC CLEAR CONDITION
- When the OK idling cycle was completed 40 times in a row
- When "Clear Memory" was performed
MALFUNCTION INDICATOR LIGHT CLEAR CONDITION
- When the OK driving cycle was completed 3 times in a row
- When "Clear Memory" was performed
FAIL SAFE
None
ECM OPERATION AT DTC SETTING
- Memorize the freeze frame data. (For test mode $02)
- Memorize the diagnostic value and trouble standard value. (For test mode $06)