P0037
Heater control circuit
Low bank 1 sensor 2
Now as far as I’m aware that’s the sensor to the rear, not the one that’s fitted to the headers but someone has pointed out that this description of the code is not accurate, e.g the use of heater circuit and sensor 2 as that sensor is not part of the heater circuit.....whether that’s true or not I’m not sure and whether it matters I’m not sure as the code seems to be for the rear sensor.
Can anyone shed any light on this as to why it would describe the sensor 2 as being part of the heater circuit when it’s apparently not?
Low bank 1 sensor 2
Now as far as I’m aware that’s the sensor to the rear, not the one that’s fitted to the headers but someone has pointed out that this description of the code is not accurate, e.g the use of heater circuit and sensor 2 as that sensor is not part of the heater circuit.....whether that’s true or not I’m not sure and whether it matters I’m not sure as the code seems to be for the rear sensor.
Can anyone shed any light on this as to why it would describe the sensor 2 as being part of the heater circuit when it’s apparently not?
Nothing to do with the cars heater. 
Each lambda sensor in the exhaust, be it, the A/F sensor in the manifold or the after cat oxygen sensor, it has it's own heating circuit to bring it upto working temperature quickly.

Each lambda sensor in the exhaust, be it, the A/F sensor in the manifold or the after cat oxygen sensor, it has it's own heating circuit to bring it upto working temperature quickly.
I was told the rear sensor doesn’t have the heater, hence why it’s supposedly not an accurate description “heater circuit low bank 1 sensor 2”......but is the heater circuit just a generic description regardless of whether sensor 1 or 2 is faulty or does the rear sensor have in fact, the heater?
Yes they both have heaters as Don says. As a rule if an 02 sensor has more than 2 wires it has a heater
It is quite possibly fused and you can test if you have power at the plug.
Last edited by 1509joe; Jan 31, 2018 at 11:53 AM.
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I sent the picture above to someone and they mentioned that it was a conflicting description which got me thinking, but you folk have confirmed otherwise and after googling it most others who have had the same P0037 code the description was the same on their scan tool....”heater circuit bank 1 sensor 2”.....
Was actually thinking that do you not use that car for track work. Was wondering why you still had a cat in place. If the cat isn't there then the sensor is obsolete so you need it mapped out otherwise cel. You could mess about with resistors but a pain in the ****.
Standard Subaru description for DTC code P0037
ENGINE (DIAGNOSTICS)(H4DOTC) > Diagnostic Procedure with DiagnosticTrouble Code (DTC)
DTC P0037 HO2S HEATER CONTROL CIRCUIT LOW (BANK 1 SENSOR 2)
DTC DETECTING CONDITION
etected when two consecutive driving cycles with fault occur
ENGINE (DIAGNOSTICS)(H4DOTC) > Diagnostic Procedure with DiagnosticTrouble Code (DTC)
DTC P0037 HO2S HEATER CONTROL CIRCUIT LOW (BANK 1 SENSOR 2)
DTC DETECTING CONDITION
etected when two consecutive driving cycles with fault occurThread
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