dervdoc

diconnected the 3 sensors in the engine bay and all 3 are getting an earth, my 02 sensors all have 4 wires, 2 black one white and one blue, when i rang out the 2 black wires bank 2 sensor was the only one that didnt show open circuit/high resistance, also on the off chance i checked the Vvti filter, was blocked so gave it a good thinners bath, hard to say if it made a difference as when i get her up to speed the management light comes on due to the o2 sensors, only think i aint checked yet is if the sensors age getting power yet

going by the wiring diagrm these 3 sensors do share a common earth, my guess is someones had a poke about when they have decated or changed the throttle body or i have a nipped wire somewhere in that area, will get a good look tomorrow see if i can source the problem

as i said in another thread im getting these codes

P0135 Oxygen sensor heater malfunction circuit bank 1, sensor 1

P0141 Oxygen sensor heater malfunction circuit bank 1, sensor 2

P0155 Oxygen sensor heater malfunction circuit bank 2, sensor 1

bit funny she threw up for 3 sensors that have the loom in the engine bay yet bank2 sensor 2 which has sits loom seperate up through the floor isnt mentioned, maybe i have damage in the loom? or would these sensors use a common earth for the heater circuit?

or maybe 3 are just knackered on the off chance,

anyone roughly know wat resistance values i should find if i unplug the sensors and ring the heater circuit wires out?

if one sensor is away will the mk2 gs300 usually fire up just one code for the problem sensor or can it trip codes up for other sensors?

anyone deact'd there GS300, just wondering did it cause any engine managemant light trouble, any o2 sensor faults? or has it cause no troble in that side of things?

right iv fixed the blow out in the exhaust, still seems to be the same,going to look more into the o2 sensor side of things,

I'm assuming if it has been decat'ed, then all sensors would trip. If the ecu is tryig to cut everything back to try and get the sensor readings in scope, then that could explain the lack of power. I would've thought a decat would need the sensors disconnecting and something plugging in in their place to fool the ecu. If the ecu is trying everything it can to get the right readings, and failing, it can only assume the whole thing is knackered and go into a limp home type setting.

this is basically wat i have been thinking, only way is to fool the ecu into thinking its reading perfect lambda, alot of amgles to look at

So did you buy privately? Did faults not show on test drive? Not trying to come across wrong but you must have some redress depending on how you purchased the car.

i took it as a trade in, new it needed work, so isnt standing me much.

right, i plugged in today, fault codes are as follows

P0135 Oxygen sensor circuit bank 1, sensor 1

P0141 Oxygen sensor circuit bank 1, sensor 2

P0155 Oxygen sensor circuit bank 2, sensor 1

also got more info on the history of the vehicle, both ''cats'' have been gutted, and there was a problem with engine reving and cutting out but the previous owner replaced the throttle body and this was cured but engine really lacks in power since it was fitted,

any ideas?

it seems funny of all o2 sensors to be throwing up faults not unless the ''de-cat'' has affected readings, they all seem to be pluged in tho, only thing i dont know is if these faults where actice before the throttle body was replaced and the de-cat was done,

any help would be much appreciated,

owner had access to a rolling road and she only made 136 bhp, no where near the factory 200+

never splutters, idles perfect

newbie here people, just bought a year 2000 lexus GS300 Sport, 6cylinder naturally aspirated,automatic,

starts perfectly, no hesitations, no splutering or misfires but seems really really dead compared to wat she should be like,

the engine management light is on but will try get the code reader on her tomorrow,

anyone came across this before, maybe something simple.