Hi all,

Just the other day I got a P1135 code.

With money not exactly growing on trees, I’ve been looking at some of the Amazon alternative air/fuel ratio sensors compared to the Denso brand.

Does anyone have any experience with the cheaper alternatives? Where are the corners being cut on the 40-65 dollar sensors?

Don’t get me wrong, I’m the first to say buy quality. But let’s face facts. These 3rd Gens aren’t getting any younger, and living in the northeast does help them either.

I’ve recently sunk a bit of coin into mine in the form of brakes, exhaust, lower ball joints, outer tie rods, oem rack and pinion (whole other story), valve cover gaskets, tires and finally stainless steel rocker panels. I would actually say I’ve invested more than the truck is worth.

Another 125-150 is going to be tough to swallow.

Sorry for the long post.

Scott

I would keep my eyes peeled on Fleabay then for one. Unfortunately the 4Runner in my experience doesn’t like non OEM or OE maker parts. You may be able to hit a yard as well and find a newer installed one. Check the forum boards as well.

We had some users have major issues with Amazon super cheap ones being complete knock offs. Even Ebay can questionable for knock offs.

For example:

Rock auto has the denso sensors for under 50 bucks for 98 v6 and they are genuine Denso. ;)

2002 downstream not bad but that upstream one runs $117. Wide band sensors cost more then the narrow band ones. :[


So might be best to shop around if the budgets are tight for slightly used. ;)

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I don't think anyone on this forum is going to suggest trying to save money by buying aftermarket O2 or Air/Fuel Sensors. People that have tried have had problems and ended going back to a Denso which in the end cost them even more money. Do it once and do it right.

Thank you for all of your input. It makes sense to get the denso part. I learned that this summer with my rack and pinion. Two reman units blew out. I ended up getting one from my local dealer.

Thanks again!

That's what l learned 25 years ago. On Toyotas best to use OEM or OEM mfg parts only. If not, that exactly what ends up happening. Your change the same part a pile of times. :[




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Can a P1135 cause a high idle issue?

I screwed up and put an NTK sensor in my 97. It seems ok.


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What year is your 4 runner?? The reason I ask they are different in the later years and CA emissions then the early years and federal emissions

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As long as it functions properly it will work. It's a shame there is so much Junk out there today. I also think the narrow band are not as fussy as the wide band ones as well too..

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It’s a 99 3.4l

I got this from Tacoma world.


The P1135 code is the heated portion of the front O2 sensor(s) malfunction... either shorted or open circuit. The ECM provides the ground and it monitors the voltage that is required to operate the heater portion of the front O2 sensor(s). If a 4 cyl, one front o2 sensor, V6, 2 front o2 sensors duh... anyway, there is a resistance spec for this and it is usually a pretty narrow range of a few ohms, check this first. Then check for 12v at the harness, you are going to have to get a wiring diagram to ID the correct wire(s). The next step is to disconnect the battery and let her sit for some 5 minutes to bleed down any capacitors in the ECM. Locate the ECM and disconnect the plug. The pins/connectors are pretty delicate so dont go poking around with screwdrivers and distort anything. Locate and ID each wire that goes to the O2 sensor you are checking and check for continuity, and shorts... you might have to exercise the harness to see if there are any breaks in the harness that you cant see. If all checks out OK I would check for how good the grounds are for the ECM and follow them to where they actually connect... Check the ground off of the battery to the block, the little ground off of the battery to the chassis, right by the battery and the ground from the firewall to the back of the head/block. The next test requires a decent volt/ohm meter... you will need to check the voltage drop from the ECM ground(s) to the battery... If there is a high voltage drop the ECM gets electronic noise, clutter, confused. This can be eliminated by a new ground wire from the ECM ground point to the negative post of the battery.


So I cant give you a yes or no answer on the high idle.




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I would say yes. The heater fail in the front A/F sensor will likely keep you in open loop as the ECM will reject the sensor input and block the transition to closed loop. The fixed map in open loop will probably be too rich as the engine warms resulting in a high idle. A live scanner will show if you are in open or closed loop.

P.S. P1135 tells you it is California emissions, no need to ask.

So you can use the FSM to test your O2 sensor and see if it passes the spec or not. Maybe a busted wire.

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On a carbureted engine it rich causes a low idle and blubbery acceleration. These engines run around 12:1 AF in open loop warmed up to prevent leaning out and melting a piston. WOT on my 97 is 12:1 running that too long can gas your oil.


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