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Check Engine Light - 2000 Camry
October 26, 2007
CHeck Engine light came on around 95K miles. Havent been able to get to a mechanic but hate to go in without a clue. I'm now at 100K miles - could it be the O2 Sensors ?

October 29, 2007#1
You can take it to an auto parts retailer - like Checkers, O'Reilly, Autozone, AdvanceAutoParts, etc. - they can pull the CEL code for no charge, though by practice, they cannot erase the code. Dealerships generally charge a flatrate "diagnostic" fee before they even touch the car - usually runs anywhere from $80-$105 - depending on where you live at. You could also pickup an OBD-II scanner at most autoparts, Wal*Mart, Sears, etc. - the basic ones usually run about $50-$60 - not a bad thing to have at home, will pay for itself after one use (compared to the diagnostic charge).

As for what it could be, without pulling the code, be like a shot in the dark - best to take it somewhere to pull the code, as it could be just about anything at this point.

October 29, 2007#2
The only issue there is that some codes are proprietary and for those, you'd need a proprietary scanner. Some transmission places have those, but most regular shops dont. Still, I'd go for the free reading and if its one of those awful "There's something wrong and if you worked at a dealership I'd tell you what it is" codes you can THEN go to the dealer.

The universal code readers can often do much more, and are worth the investment. Here are two that I tested myself:

November 8, 2007#3
Finally made it to an Auto Zone. Turns out to be the O2 sensor after all.

Might you have a diagram for where this is located ?


November 8, 2007#4
Which one (what code was stored) the upstream one or the downstream one? Description should have noted O2 sensor, Bank 1 Sensor 1 or 2, etc.

The one you should se sticking out pretty obviously under the hood (sticks in the exhaust manifold before the catalytic converter - the other should also be fairly easy to see - should be sticking out the side, right after the catalytic converter.

November 8, 2007#5
The code they gave me was P1135

November 8, 2007#6
Good deal - a P1135 code says something like A/F Sensor Heater Circuit Malfunction (Bank 1, Sensor 1). Assuming this is the 2.2L 4 cylinder engine?

This is the sensor infront of the catalytic converter (upstream one - B1S1). The sensor behind the catalytic converter would be a B1S2 - if you have the V^ engine, then you have Banks 1 and 2 - though I dont remember offhand which side Bank 1 refers to.

Many people who get this code on Camrys and Lexus RX300 SUVs have found that the sensor's resistance has falled out of spec (open heater element inside the O2 sensor). Replacement usually fixes it right up.

If you do replace it - probably a good idea to replace it with an OEM type Denso sensor. Many with the same code have found out the hard way that Bosch and Denso Universal ones run slightly higher resistance than the OEM Denso ones (direct plug in type - the more "expensive" one). That resistance causes the same or additional CELs to come up. After the fix - a good idea to reset the ECM to clear the codes and monitor it to see if it comes back or new ones are generated. Good Luck.

November 9, 2007#7
Wow - did some searching...

Turns out I have a Cal. emissions vehicle and the price is substantially higher.

Bosch runs about $156 while Denso is $269 [ AutoZone]

Is there that much of a difference between the 2 ??

November 10, 2007#8
According to what I've seen from other Camry and Lexus owners in the same generation as your Camry - Denso are the only ones that run the correct impedance. The Bosch do not seem to work for some reason - but I cannot say for sure it will be the case with your application.

Might want to ask the parts guys if you can exchange the sensor for the other - in case the cheaper one doesnt work. If they OK it - get it in writing - as I know Autozone and many others have policys that prevent some electrical parts exchanges.

Call around, search online - should be able to get a better price than those listed, even for the Cali spec ones. I've seen universals listed at around $100+, with OEM ends around $150+ in Denso, ACDelco, Bosch, and some others. Note that the universal O2 sensors do NOT have the harness included, just bare wires. You will have to cannibalize the old, original harnesses to make them work. Unless you know someone that can solder well - better to spend the extra money for the OE type O2 sensors.

Also note that there are also some Wideband O2 sensors out there - those will run around the $250 to $300 price range - for some reason, it pops up as a replacement O2 sensor for the Camry. My experience tells me this info is incorrect, as widebands are mostly used with more advanced aftermarket ECMs and its signal levels are inconsistent with what the factory ECM are designed to work with. They also have an incredibly short lifespan (less than 30K miles), as they are designed for range and sensitivity, not long life. Widebands are what you use to fine tune the air/fuel management on a project car. Once that gets sorted out - then you can replace it with a regular O2 sensor.

If in doubt - ping a Toyota tech for info. They should be able to provide you with part numbers when needed and any additional info that might be useful for you down the road.

November 13, 2007#9
Just when I thought I had this down....

Called the local Toyota dealer - turns out my Camry has Cal. Emissions. They say the sensor up front is called an Air Fuel Ratio Sensor, and this runs about $235.

Is there that much of a difference between a California and a Federal emission system ?

November 14, 2007#10
Not a whole lot - generally with this generation of Camry, the differences are like fresh air injection into the exhaust system to promote further emission control and small differences between the ECM programming. They pretty much did away with the differences with newer generations since stocking parts for essentially two different emissioned cars was a royal pain.

I've never heard of them referred anymore as air/fuel ratio sensors (outside of older texts and articles) - generally they mark them as oxygen sensors (O2 sensors). As you cannot really measure the amount of unburnt fuel directly - but you can measure much oxygen is left in the exhaust.

A better description can be found here:

Have them give you a part number for the sensor - then shop around for a better price for it. There are many online retailers that are actual physical dealerships - many times they will sell items online at significant discounts.

November 21, 2007#11
OK - after some online shopping around, found a good 'deal' - saved $70 from what the dealer wanted to charge, got the part, installed it, and no check engine light !

Appreciate all your help.

November 24, 2008#12
Chris, where did you purchase and install the sensor?


December 8, 2008#13
I purchased the sensor at

As it turns out, my vehicle has California emmissions, so the part turns out to be an Air Fuel Ratio sensor - with basically meant it cost more.

Whomever you use to buy parts from, have your VIN checked out to determine if it falls into this as well.

The actual replacement was simple as the sensor was in the front of the manifold.

Good luck.

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