johnnylt

Check engine came on vsc / traction etc- took to local mechanic put on scanner only one code came up p0134 bank one oxygen heat sensor replaced it cleared the code was fine drove for 2 days 7-8 start ups check engine light back on with vsc/ traction etc ? What gives ? He said maybe bad denso part ? What do you think club ? Bad sensor ? Another sensor? Cost $200.00 to replace ?cant stand those lights on my 05 ls430 flagship bullet proof !! Only 99,000 miles well taken care of baby mint condition never in snow sits in garage in bad weather please help

mrboca

Maybe the O2 sensor is not the problem ? This code can come up because of intake air / exhaust leaks, fuel pressure / plugged fuel injector issues (as well as O2 sensor problems). However I would have eliminated the other possible reasons before automatically replacing the sensor.

Do you remember what recent service / repair / maintenance was done prior to the CEL?

johnnylt

thanks guys I appreciate all the tips , when he scanned my car it came up that the sensor in bank one had zero activity ,I think that's why he changed it out ,and then he hooked up the scanner again ran it , zero codes came up , everything fine . then like I said couple days later its back on?

johnnylt

hello again, I don't know if this will make a difference we took off the covers from the engine and found the PCV valve completely disconnected?

mrboca

Of course it does matter. I was just writing to you that your mechanic seems to be treating the symptom, not the cause. I am surprised you did not have rough idle with that condition.

I would do the following.

1) remove the PCV valve and clean / replace and re-install. Make sure you order the plastic grommet with the PCV as it usually gets brittle.

2) connect the PCV hose.

Why would the PCV hose be disconnected all by itself ? I had a hard time to remove it from the PCV valve end

3) As you probably did not use the car for long periods of time, the fuel in the tank, filter, injectors got a bit gummed up. I would use a bottle of Techron (or Berryman's B12- Chemtool from Walmart for $3) and fill the tank and drive around as your fuel lines are cleaned up.

4) If your CEL does not go away, I would check for additional vacuum leaks, or fuel supply issues.

5) Clean / replace your MAF if you have not already done so, and make sure you clean the correct part two components (inside the tube, as well as the outside the tube intake air temperature sensor with MAF cleaner.

johnnylt

thank you for your response/ PCV valve cleaned and re-installed , took apart the mass air flow and cleaned that, checked all hoses and vacuum lines , all look very good , cleared the code out ,started car everything seems fine . I hope this resolves my problem and my Flagship will be back to normal !!
I will drive to work tomorrow with it ,and pray that light stays off, mechanic said everything is fixed I hope he is right...

mrboca

Hopefully he looked at the long term, short term fuel trims and made sure the total fuel trim is within range (+/- 5 percent while at idle at full operating temperature). Long term operation with rich or lean fuel mixtures needlessly destroy your catalytic converters.

I am sure your mpg will improve with the fixes.

johnnylt

So far so good I will see tomorrow when I drive to work. Miles per gallon not bad I was averaging 20 mph in the city in very light on the gas also I will try switching to no instead of shell I always put 93 octane in it maybe with this pcv valve corrected I will not get that bad smell at hard acceleration any more.
Ok will see tomorrow I will report back