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The "check engine" light on my 2001 Sienna recently flashed on, and, before I had a chance to intervene, my wife took it in for its annual safety inspection and emissions test -- which it of course failed. Checked the codes and got: P1130 - A/F Sensor Circuit Range/Performance and P1155 - A/F Sensor Heater Circuit. Been poking around on the internet, and I've learned that the 1130 code might not necessarily indicate a bad sensor, and I also get the impression (though it's hard to decipher some of what I've found) that the 1155 code might be directly related to the 1130 code (that is, one may be causing the other -- or both by a third problem). Any insight into this issue would be greatly appreciated since I'm not too excited about spending $300 to $400 replacing these parts if the part is not the problem...

Thanks!  

trouble codes does not necessary mean a failed component but rather a CIRCUIT fault.  

this can get a bit tricky DTC P1130 is indeed an A/F sensor code(bank 1 , sensor 1) DTC P1130 is a A/F sensor heater circuit(bank 2 , sensor 1)however it refers to DTC P1135 for diagnostic procedures, not P1130, if your vehicle has the service engine soon light on or a stored current emissions related code ,it will automatically fail, even it the problem was momentary and no longer exists(oxygen sensors are good for that) hitting a puddle of water will slow them down enough to cause a code, these codes involve both banks so it is possible there is a problem, but it may have been intermitten, if the vehicle is running well still, diagnosing requires a scan tool capable or reading the data stream, so unless you happen to have one , your kinda up the creek, if you can get the code cleared and the light is off, it very well may pass
NOTE: RUNNING OUT OF FUEL WILL SET DTC P1130  

If you have a Auto Zone in your area they can scan and reset SES light.
Or disconnect battery for a while. See if SES comes back on.  

the codes P1130 and P1155 both refer to Air/Fuel which air flow to your engine starts with your air filter if it needs it replace it and that should cure the problem then take it and get the codes reset. i know it sounds like im joking but im not ive seen it a couple of times were a service engine light will come on if the air filter get dirty  

I recently had the code p1130 which is air/fuel ratio sensor bank1/sensor1, but instead of replacing it I took it out and noticed it had white carbon deposits and the wholes on the a/f sensor were clogged.  So I took a light sand papper and sanded the carbon off and then sprayed it with carb cleaner wiped it clean and let it dry, haven't had a problem since and it saved me $200.00. I hope this helps!  

P1155 - A/F Sensor Heater Circuit, is the heater circut on the HO2S (Heated Oxygen Sensor).Before you know if you should replace the HO2S, you will have to test that circut at the sensor connector and, to do so, you will have to know which wires to test, which you will need service info for. In the process of testing, you will probably spread the terminals inside the connector, and end up taking it to some hack garage where some goober will just mess it up more before he fixes it for some outragous price.

P1130 - A/F Sensor Circuit Range/Performance. This code is set when the inputs from a specific HO2S is outside a set perameter. This is usually caused by the sensor failing.

If indeed, these two codes are set from two seperate HO2S's then you could be looking at a complicated diagnoses, best done at a DEALERSHIP!  

Hello Patches:

How difficult was it to remove the Sensor. Any and all tips are welcome and appreciated. Thanks
Sam  

sam... thats an old old thread....    chances of them answering .. nil.....

but... there are a few current people here...



got an autozone near by.??? other stores have similar tools..  and this tool does not fit every application.. but it is a tool that does a good job getting out stubborn hard to get to ones...

they have an oxygen sensor flexible wrench...
Description: Great Neck  O2 Sensor Wrench
Part Number: 33625246
Sku: 947305
30 bucks... hanging on the tool isle..   they also have loan a tool program with several oxygen sensor sockets..

now.. to get the oxygen sensors out...    i try to loosen them... if the don't move.. i tighten them a *** just enough to move them... then loosen them...   getting the connector unhooked... that really is HARD on some cars...  easy on others...



if you have a 2000 to 2006 sienna...

here is a link to a picture of the oxygen sensor locations on the exhaust manifolds..

http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0900c152/80/19/7a/f6/medium/0900c15280197af6.gif
there is something else that you need to know...  there are several things that can cause the oxygen sensors to set a code....

get the codes from the computer... write them down...   with a scan tool... you can see a snap shot of what the engine was doing when the code set...   that sure makes it easy to diagnose an intermittent failure...  

there are dozens of flow charts to follow for each code ...  so you don't end up replacing stuff thats not wrong...

alldatadiy.com     and    eautorepair.net  have the charts online.. for a small fee...

any OBD2 scan tool   or EOBD2 scan tool can look at sensor voltages and other emission controls on that car..  it cannot be fixed properly without it...