Voltage of lambda probes

dzikuss

New Member
Hi! I made a test with VCDS to check the condition of lambda probes before and after cat.
Is it normal that Bank1 Sensor 1 (pre-cat) probe shows voltage on 033 group ( if I remember correctly) about 0.45V +/- 0.05V? The reading doesn't change if engine is warmed up..
Another question about Bank1 Sensor2. This probe on VCDS 036 ( if I remember correctly) shows different values from 0.1 to 0.700..It is jumping. Depending on rpm, basically. When the CAT is warmed up till 300*C, it shows approximatly 0.7V in idle, but if I wait for some time this value starts to decrease ( I guess this is because temperature off CAT starts to drop).
The main problem I have is problem with emissions - HC ~100; CO ~400. I change the cat for now, but I want to be sure before next emission test..
Before CAT change (I changed it today) there was intermittent fault according to Bank1 Sensorr2 - "limit reached" or something like this, meaning that oxygen is high in exhaust..

Tnx in advance.
 
Generally an O2/Lambda sensor will read between 0-1v. The actual voltage is not important, what is more important is that it moves above and below 0.5v, depending on whether it is indicating rich/lean. Therefore, static usually means broken, continually flicking up/down is good.
 
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