Sensor Proficiency Unlocking the Power of Normal Readings

Anyway, the downstream O2 should be somewhere in the middle (0.45V) if the cat is still there. The AF sensor though, as per the FSM, fluctuates ... Oxygen sensors will run from almost 0 volts up to around 1.1 volt. I'm not sure why it's reading over 2 volts, but some aftermarket diagnostic tools can be a ... Normal O2 Sensor Voltage Readings. The normal voltage range for an O2 sensor fluctuates between 0.1 and 0.9 volts. This isn't a static reading ... All the O2 voltages over 1 volt are off-scale high (rich). While in closed loop mode, both sensor 1 voltages should be oscillating from around . A properly functioning oxygen sensor will show a rapidly fluctuating output voltage between approximately 0.1 and 1.0 volts. ... sensor is properly detecting the PCM's normal, frequent fuel mixture alterations. For now, forget about the downstream O2 sensor ("B1S2"). I swapped out MAP sensors just to see what it would show, stock one was at 28.1HG and the 'new' one was at 27.7HG. 1996 Pontiac Firebird - 3.8L, ... My o2's do that as well.. i think it's normal. One will read .0xx and the other .9xx at a given second. 1995 Z28 Camaro ... the traditional B1 S2 sensor. The rear sensor, S2, reports voltage in the manner you described. The front sensor, S1, can report in several ... The wave form looks normal. It is averaging the fuel mix, and not stuck rich or lean. Did you install aftermarket cat, possibly a higher restriction.