The BritishV8 Pub

Wife's 03 Highlander check engine light is on and it's showing P0135 code - decodes to bank one, sensor one. OEM replacement (Denso) as well as Bosh & others that are "direct fit" run about $135. I found this site that has "universal" sensors with the one for 01-05 Highlanders being only about $40. According to the sight, I'd just need to splice the connector from my existing one. [www.autopartswarehouse.com]

So, the question... I can splice wires; any reason not to go with the universal one?

Rob,

Apparently there is a difference between the upstream and downstream sensors. Given that caveat, everything that I have read is that the universals are manufactured by the same companies as the OEM.

Wires is wires unless they have some built in rerference resistance, but everything that I have read indicate that is not the case. If it were me, I'd go for it.

Yeah, the code I'm getting is for upstream & this generic sensor says it's for before the cat so that much should be right.

Rob, I'll try to find the post that I answered some time ago on the same issue, I also had attached links to some websites explaining why universal 02 sensors are a bad idea and I strongly agree with them because of many problems observed in our large fleet at my work. Because a code comes up doesn't always mean that the sensor is at fault; for example, the code definition probably states the word "circuit" when referring to that sensor location. There's many ways to confirm if a sensor is bad and for many reasons explained by reputable repair shop magazines, oxygen sensors are not all created equal.

IMHO, oxygen sensors are crucial sensors that must operate at peak performance. Furthermore, when you install an oxygen sensor (let say the downstream for ODB2) that is of a different brand than the upstream, there's quite a bit of unseen and unspoken problems that can develop as we have found out at my work. Again IMHO, I would not hesitate to spend the extra money for a sensor directly calibrated for your vehicle. Some manufacturer will recommend to replace the 02 sensors at a certain mileage as it loses it effectiveness, they have a coating that can wear or get contaminated.

If you have a friend that owns a quality diagnostic instrument, such as the Snap-on "Modis" or the OTC "Genesis" you can verify the output of the sensors and the most accurate way is to use the lab scope that is part of the "Modis" and watch the 02 waves. The upstream sensor should display a consistent waves and the downstream should maintain a flat line after it reads coming out the catalytic converter. The downstream's function is to mostly evaluate the converter's efficiency but also works in cooperation with the upstream sensor. Not always, but in some cases, you get what you paid for; and in my opinion, this is one of them case.

I hope that others can chime in on this issue, but today's modern engine have lots of these sensors work for the efficiency and the emission side of an engine, such as ODB2 and the later CAN system........(complicated science)

Cheers

I'd tend to agree with this. If you shop around a little you can usually find a fairly reasonable price for the direct replacement sensor.

Jim

Rockauto has the original OE supplied Denso sensors for typically $50-$60.

Denso # 2344215 $52.65



Edited 1 time(s). Last edit at 02/04/2013 10:13PM by ex-tyke.

I looked at the Rockauto prices for Rob's part and it looks like it was over $100. The senors for my '02 Tahoe were about $20 - go figure.

Thanks - probably eves me a bunch of hassle! I'm going to go with the Denso... Next question is whether there's a reason to replace both banks or just the one that is showing the fault. Motor is a V6 with about 110k miles on it.

Rob, once you determine that it is in fact the oxygen sensor that is bad and not anything else in that circuit such as proper voltages, ground and etc.,, then considering the vehicle's mileage, I would replace both sensors because you want them to generate fresh and strong signals to coordinate their efforts towards the ECU's response.

I imagine that the vehicle only has two O2 sensors and not four like most GM and Ford V8 (which can be quite expensive to replace all) so it should not be too bad on the pocket book and give you a slight improvement in fuel mileage. If you check the recommended scheduled maintenance to replace them, I think that you'll find out that you're within their mileage recommendation. Too bad you don't live near me, I'd show you how to play around with the Modis scope and what to look for in the different signals.

Cheers

I had a Toyota Tundra 2002. The O2 sensor do go bad. After a 100 tho miles, I replaced with oem O2 sensors both at the same time. I first disconnected the battery for awhile, re-connected which resets the computer depending on year, later models and other manufactures make it so they are the only one's that can change them and reset the code(the engine will not start if you diconnect the wires and install new 02 sensor then try to restart). The engine light went out for a day or so then came back on. The fix ...change O2 sensors. If you go the route of wiring your own after market 02 sensors, make sure you wire them right, could possibly fry the computer..ECU...ECM..etc.

Rob find the right part number and price check on the net for the best deal and maybe no tax!