When driving got code P0135 and check engine light came on, the best explanation I found was this:
"The heated circuit in the oxygen sensor decreases time needed to enter closed loop.
As the O2 heater reaches operating temperature, the oxygen sensor responds by switching according to oxygen content of the exhaust surrounding it. The ECM tracks how long it takes for the oxygen sensor to begin switching. If the ECM determines (based on coolant temp) that too much time elapsed before the oxygen sensor began operating properly, it will set P0135."
I measured the heater resistant to be 9 ohms on the two white cables.
With motor running there was 12V on one cable and 0.3V on the other,
so the heater circuit is working OK, then checked for bad connections,
but none was found. Cleared the code with scanntool.
Next day the P0135 came back, but not when starting engine, but under driving.
I then took some snapshots of the scantool, and it shows that the O2 sensor (B1S1)
is getting tired of sending signal when it warms up.
It will stay around 0.5V and STFT shows 0V, this must be Open Loop mode.
I did it again the next day and again the O2 sensor is fluctuating at start,
but again gets tired.
The O2 B1S2 after the cat shows rich when the error occurs.
The O2 sensor has run 60K km, and needs to be replaced.
[Last edited Apr 29, 2016 11:34:17]