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anybody out there with their check eng lights coming on? mine came on about a month ago, according to the dealer my oxy sensor went out, installed new one problem solved. today, after about a month, the darn light comes on again. i'll be taking it back to the dealer this weekend.
 

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John,
did you change your intake?
Chris
 

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chris,
i installed the k&n fipk II about 2 months ago. do you think the filter is causing it? does it cause the oxy sensor to fail?
 

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John.

your K&N FIPK might be the problem. i know that "some" of the tundra owners w/ the same kit had the same problems. when you installed it did you disconnect the battery for it to reset the ECU? also, i met a tundra owner this pass weekend that found two holes in his FIPK that weren't completely drilled out. you might want to look into this as well. let me know how it goes!

Chris
 

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Toyotas can be notorious for throwing the "Check Engine Light" if you rand the engine with either the gas cap or oil refill cap off or loose. If this is the case, then the code will reset itself after the engine has run several times and the ECM has not seen the code again.
 

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There is a simple procedure to check the engine fault codes using a paper clip on my MR2 when you get a "Check Engine" light. Isn't there a similar technique for the Sequoia?

And I see no way that a air filter change could cause a problem with an O2 sensor.
 

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the 02 sensor is right at the entrance of the tube that the open air filter connects to...some say that open air cone filter sucks in too much for the 02 sensor to handle causing the failure...
 

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quote:
Originally posted by Simias:
the 02 sensor is right at the entrance of the tube that the open air filter connects to...some say that open air cone filter sucks in too much for the 02 sensor to handle causing the failure...

That's not the Oxygen (O2) sensor, that is the Mass Air Flow (MAF) meter. The oxygen sensors are located in the exhaust manifolds and in the exhaust pipes just downstream of the front catalytic converters (total of 4 O2 sensors).

Anyway, there is no way an air filter change is going to affect the O2 sensors. There is a slim possibility that an oiled type air filter could contaminate the heated wires in the MAF, but this is a very remote possibility. If that is the case, the MAF can be cleaned with some spray type carb cleaner.

The main problem I see with these aftermarket airfilter assemblies that replace the stock airbox is that they don't exactly match the cross sectional area of the pipe where the MAF sensor mounts. The air inlet tube is about 3" in diameter except where the MAF sensor is mounted and there it is compressed about 3/4" at the top where the sensor bolts on. The MAF sensor just measures air temperature and air velocity and then the computer calculates the mass of air flowing into the engine based on the cross sectional area of the pipe at that point where velocity is measured. If you go and enlarge this pipe at that point, the computer has no way of knowing that and will calculate mass air flow based on the smaller pipe when in reality you will likely have more air flowing past the sensor than previously. This could result in a lean condition until the computer remaps the fuel curves (using input from the oxygen sensors) for a given throttle position (assuming it has the capability to compenstate for that amount of increased air flow). This remapping evolution takes some time though. This is one reason it is a good idea to reset the ECU during mods like this (just disconnect a batter terminal for 30 minutes or so) which resets the fuel curves back to default values which are typically richer than normal. These richer fuel values allow the truck to continue to run without damage in the event of an oxygen sensor or other sensor failure. Once the ECU is reset, it will begin to "re-learn" the optimum fuel settings based on new input from the available sensors.
 

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Don't spray Throdle Body or Carb cleaner through the MAF it is stated on the cans it is bad for it!!
 

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okay i feel stupid now! i knew that was the MAF. i wasn't thinking when i had posted that! thanks for clearing that up, arkie6.

also, thanks for your input. what you had written about the MAF is what i was getting at, just mistakenly mixed the 02 sensor and MAF up. btw, i didn't know that there were four 02 sensors...

again thanks,
Chris
 

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First real problem

My check engine light has come on three times now.... in less than a month... got to be a problem there....

1. Late Sept. light came on, for no reason;
I just figured it was the gas cap.. (disconnected the battery to rest) I have not done any mods recently.

2. 2 weeks later, light came on again!
Right in the middle of a rain shower. So I thought problems!!
But did not have time to take it in and reset it til' I could make it in. (Reset it again)

3. 1 week later TODAY during a nice cool sunny day..
The light pops on....
Must be something wrong.. Looks like I am headed to the dealer this weekend.
This time I'm leaving the light on....

I'll let you all know what they say.
Any one with any suggestions anyway?
Lucky for me I am still under the 36K warranty.
 
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