Help required with p0031 test values

Subaru WRX STI 2012

HI all, I have an engine light with code P0031. My scan tool is showing the measured voltage and resistance of the HO2S 1 is good. I have the following test data:-

$1B
Minimum 0.000K ohms
Maximum 0.050K ohms
Measured 0.032K ohms = Pass

$1A
Minimum 0 cnt
Maximum 500 cnt
Measured 0 cnt = Pass

$19
Minimum 0 cnt
Maximum 250 cnt
Measured 266 cnt = Fail

Can anyone please tell me what the cnt measurements could be? This is the only information that my scan tool gives.

Thanks in advance.

Martin, the zero results on $1B and $1A would suggest that those tests haven't completed, despite the 'Pass' result. The fail result of $19 would suggest a definitely lack of current flow.

You say that the scan tool shows the measured voltage and current of B1S1 is good. Do you mean the scan tool itself, or a mulitmeter? Unfortunately, there's no scan tool function that I know of, EOBD or OEM, that will test for voltage and current at the O2 heater.

Have you tested for power and ground at the O2 connector?

Thanks Tyler,

The $1B measured 3.2 ohms this was also verified using a multimeter. This is why I’m confused. I measured 12v feed to the sensor and 3.2 ohms across the 2 black wires.

I haven’t checked a ground as I thought it grounded via the headers

Fitted new sensor relocated into downpipe. My tuner thinks I cooked the original one fitted in my headers as I’m running relatively big power now on a forged build.

Code cleared 70 miles done, so far so good.