Can anyone confirm if the Torque app provides data stream PIDs for B1S1 and B1S2 voltages on our cars?

My plug-in OBD2 scanner provides 8 pages of PIDs, but no upstream O2 voltages. No idea how they managed to miss this. Provides upstream O2 currents (wtf?) and downstream O2 voltages. There's lambda and some upstream differentials, but I just want to see plain old upstream voltages.

Thanks,
-Michael

 

Hi Michael,

The reason you only get currents for the upstream sensors is that they are of the wide-band type, or "Air-Fuel Ratio" sensors. The current variations monitored by the ECM are how it understands not only whether the AFR is rich or lean, but how rich or lean. The current will cycle above and below 0mA, typcially between +2mA and -2mA.

The downstream sensors are the more conventional narrow-band type and simply switch their voltage high (above 0.450V) or low (below 0.450V) to tell the ECM whether the AFR is rich or lean respectively, but not the degree to which it deviates from stoichiometry (0.450V or Lambda 1). That's why you just monitor the voltage swings on narrow-band sensors.

There's a good explanation of this in some of the Jaguar Engine Management Systems manuals, which you can probably find in the large-file download area of this forum or at jagrepair.com.

Cheers,

Don

 

+1

Worry about whether LTFTs etc are OK.

Decide whether you want to understand the wideband currents or not.