Hi All
This car came to me for a MOT test via a trader. It passed but the engine light was on and i was asked to clear the codes. The codes related to o2 sensor heaters on 2 of the four sensors. The trader sold the car without repairing and when the light came back on the buyer had the sensors replaced by a local garage and the trader paid the bill. However now a catalyst efficiency code has appeared and i have been asked to have a look.I connected all four sensors to my pico and the B1S1 and B2S1 readings were both at 3.4v steady and B1S2 and B2S2 readings were switching between .2 and .8v regularly. I have gone onto the Toyota technical site and the spec. for the pre-cat sensors is as found. The problem is i would condemn the cat for the fact that the signals are switching after the cat but the emissions are perfect and i have not come across a 3.4v flat-line waveform from a four wire 02 sensor before.can anyone tell me if this is normal or do i have a fault or am i thick!
Thanks
Allan