P0140 - HO2S Circuit No Activity Detected (Bank 1, Sensor 2)

The HO2S-12 circuit is monitored by the Powertrain Control Module (PCM). The test fails when excessively high voltage from the HO2S-12 is sent to the PCM.

Possible Causes:
^ HO2S-12 circuit is open
^ HO2S-12 circuit is shorted to VPWR
^ Rear HO2S

Diagnostic Aids:
The O2S-12 PID should vary between 0 - 0.3 volt and 0.6 - 1 volt with the engine running at 2,000 rpm.