oxygen sensor???!! near cat

[leon_in_uk]

hi guys, guess what. travelling down the motorway yesterday and my EMS light came on again.... why..

i thought i could get away with calling the RAC chap out to see where it was and if i could do myself instead of the rip offs toyota..

he said my engine was running to lean.. and it was putting extra fuel into my engine to compensate.

anyway he thinks that it may be 1 of the leads running by the heat shield. thaaink called the oxgen sensor.

he also told my to take it to a auto electrician to find out which lead and also to replace it..

any1 else had this problem???

ooh and explains why it struggles a bit on 4-5k revs.

[Anonymous]

That sounds like exactly like the problem I had and corrected yesterday. Mine was a dirty MAF sensor which I duely cleaned, then unplugged the battery for 30 mins. When reattatched, the engine light was gone, and the car returned to its former glory, particularly at 4000 revs.

[leon_in_uk]

if it is the same problem your light will come on again in a bout 3 days time. i cleaned the maf sensor and disconnected and it was gone, now back on and a large fault with either the wire or sensor by the engine. i think the ecu may only read after a while, oh and the RAC tested all and its only a minor fault with the oxgen sensor, but needs to be done sooner rather then later

[GSB]

if it is the same problem your light will come on again in a about 3 days time.

With many faults the ECU will use 2 or 3 trip logic to ensure its a true problem, rather than a single spurious occurance. For example, a defective heater circuit in the 3rd o2 sensor will not show a CEL until it has been constantly active for 2 trips. Atrip being the cycle consisting of a normal engine start, run up to operating temperature, shut down, and cooled normally. If the fault exists through 2 of these cycles, then the ECU displays the CEL. The data regarding sensor operation is available immediatly, in real-time, via the OBDII port.

To be able to assist you further leon, you need to obtain the fault codes from your ECU. either by finding a friendly member witha an OBDII reader, or obtaining the codes from Toyota. Without this data, any diagnosis offered here will be a guess...

[leon_in_uk]

thanks GSB, only thing is just rung toyota, said they wanted £85 for an hour labour and if it is the sensor fault then a new 1 is between £85 and £125. are they joking,.

oh and rung an auto electrican and he said £30 and he can do a diagnostics test. will that find the codes? or the faukt which i can then buy and fit myself???

cheers

[darrenjuggins]

Leon,

Sounds very much like your MAF has died.  A new one is apprx £90 and you can fit it quite easily.

Your sensors sounds like they are doing the correct thing.  Your MAF detects the air flowing into the engine, without it, you will just be running lean (this has all been said above).

Hope you get it sorted, but Toyota did take a while to diagnose a MAF with me, it was only after I had to Lean engine warning, or fuel contimination warning that the MAF was diagonised - just warning you for the bill you may get presented with for a poor diagnoisis.

Cheers

Darren J

[leon_in_uk]

i cleaned the maf sensor. the rac bloke said the air intake temp and sensor was ok..

i am trying to find someone near tamworth, mids that has a diagnostic test and get the codes to see if i can repair myself.

as i still think it is the oxygen sensor!!

[Anonymous]

if it is the same problem your light will come on again in a about 3 days time.

Mine must have been just duuuurty as it's still ok

[leon_in_uk]

slacey fixe dmine i think. i added the induction kit on, and it must of got greasy. again.. but a clean MAF a much better car to drive

[Anonymous]

hi there lads and lasses, excuse my ignorance  s:oops: :oops: s:oops:  , but where exactly is this MAF sensor,
it sound like a problem im having too, EMS comes on when i put the boot down on motorways etc, its also sluggish on initial take off and hits a flatspot at 5k revs, but this only happens under heavy take offs, its a jap import, i dont usually drive it hard, but this is niggling me, any opinions appreciated.

cheers AL!

[Peter Wright]

hi there lads and lasses, excuse my ignorance  s:oops: :oops: s:oops:  , but where exactly is this MAF sensor,
cheers AL!

m http://www.spydermagazine.com/2002/Marc ... _clean.htm m

[Anonymous]

many thanks Peter, ill give that a try now   s:D s:D

[spit]

if it is the same problem your light will come on again in a about 3 days time.

With many faults the ECU will use 2 or 3 trip logic to ensure its a true problem, rather than a single spurious occurance. For example, a defective heater circuit in the 3rd o2 sensor will not show a CEL until it has been constantly active for 2 trips. Atrip being the cycle consisting of a normal engine start, run up to operating temperature, shut down, and cooled normally. If the fault exists through 2 of these cycles, then the ECU displays the CEL. The data regarding sensor operation is available immediatly, in real-time, via the OBDII port.

To be able to assist you further leon, you need to obtain the fault codes from your ECU. either by finding a friendly member witha an OBDII reader, or obtaining the codes from Toyota. Without this data, any diagnosis offered here will be a guess...

Looks like the curse has spread north - All this talk of CELs, I've got one now  s:x :x s:x  Returns one cycle after reset, which doesn't sound good, but the car is running ticky-boo and cool, which has settled me a little - or is this just tempting fate?

Checked and cleaned all the obvious things, but dunno what to do about it now; until Simon brings good news on a J-Spec reader, I guess I'm moderately stuffed.

Sensor down or urgent niggle? Anything I can do to narrow it down? Doesn't help that I have to pootle to Solihull & back tomorrow, so speedy "peace of mind" advice would be much appreciated.

[spit]

Panic over - got an open circuit on bank 2 O2 heater. I can live with that for the moment.

[Jap GT300]

How did you work that out without a reader?

[spit]

The sensor should be reading up to about 15Ω across the heater wires but its not.....its open circuit. I suspect the signal is still reading reasonably OK and everything else is fine as there isn't any obvious drop in performance. In fact the only problem is the CEL!

[Tem]

The sensor should be reading up to about 15Ω across the heater wires but its not.....its open circuit. I suspect the signal is still reading reasonably OK and everything else is fine as there isn't any obvious drop in performance. In fact the only problem is the CEL!

I suppose a 15ohm resistor might get rid of the CEL  s;) s;)


It will warm up slower than with the heating and will read a bit wrong till it does. It's probably nothing to worry about, just more emissions after startup.

[spit]

We're on the same wavelength Tem!

I suppose a 15ohm resistor might get rid of the CEL  s;) s;)

It would, and it did  s:wink: :wink: s:wink:  Am I right in thinking that the ECU holds the sensor in open loop until it starts reading expected numbers, or is our ECU not that cute?

[Anonymous]

cleaned out me MAF using carb cleaner, took 5 to 10 minutes,
jesus what a difference in bottom end grunt, its totally tranformed the take off characteristics of the car, no more flat spots at 5k revs or warning lights when flooring it either  s:D s:D  ,


once again cheers peter!!

[Anonymous]

what do you uise to clean the 2 wires? does the spray do it itself or do you use a brush or anything?  and then do you rinse the sensor or anything or jsut let the carb cleaner dry

had this answered so just ignore me guys

[Tem]

what do you uise to clean the 2 wires? does the spray do it itself or do you use a brush or anything?  and then do you rinse the sensor or anything or jsut let the carb cleaner dry

had this answered so just ignore me guys

Do NOT touch the wires with anything  s8) s8)  You'll most likely just break them.

(ignoring you, but answering to other who might be wondering)