O2 sensor heaters offline

[Lgibson]

So, 2015 LR4 at just over 40k and it failed emissions today for O2 heaters inactive. The IID Tool live values confirmed both banks off though no CEL is displayed. My first thought was fuses but all three were good with 12 volts present. Why both banks?
Ideas?

 

[Lgibson]

As a followup, why is is there no check engine light for “O2 Sens Not Ready” and “O2 Sens Htr Not Ready?”

 

[Lgibson]

Surprise, SO took it to the dealer and received the following report:
FOUND START STOP BATTERY HAS FAILED CAUSING FAULT TO BE STORED IN PCM PREVENTING MONITORS FROM BEING SET
REMOVED AND REPLACED START STOP BATTERY TO CORRECT
I have followd the ISS threads here religiously and never heard of such a problem. That little $400 battery has been out for a year but must have had enough left to enable passing emissions last year.
I will update the ISS thread.

 

[Waterndirt]

I run with a dead start stop battery, on purpose. Last time I check it was at 8 volts. Great info!

 

[jlach993]

Surprise, SO took it to the dealer and received the following report:
FOUND START STOP BATTERY HAS FAILED CAUSING FAULT TO BE STORED IN PCM PREVENTING MONITORS FROM BEING SET
REMOVED AND REPLACED START STOP BATTERY TO CORRECT
I have followd the ISS threads here religiously and never heard of such a problem. That little $400 battery has been out for a year but must have had enough left to enable passing emissions last year.
I will update the ISS thread.

well ill be damned lol...