runnerboy97

My check engine light came on today, and the code i got said it was an "O2 sensor slow response". it was bank 1 sensor 1, i think thats the passenger side before the cat, anyone know for sure?
What exactly does this code mean, i was told it was because the heating element on the sensor is bad, does the O2 sensor need replacing?
thanks for any help

Scooter22

Code 0133. You are right, bank 1 means it is on the same side as your number 1 cyclinder (passenger side), and sensor 1 is the oxygen sensor before the catalytic converter. As far as I could find out about what it means:
Open or short in heated oxygen sensor circuit
Heated oxygen sensor
Air induction system
Fuel pressure
Injector
Engine Control Unit

Hope this helps

MTL_4runner

There is only one bank of sensors on your truck (bank 1) so that makes it easy. Sensor 1 is before the converter (ie closer to the engine) and sensor 2 is obviously after the converter. It is not uncommon at all to have sensor 1 go out after 80k miles (some go longer) and yes, slow response can be the heating element but it could also be that the sensor's coating has been damaged over time and is thus in need of a replacement. Either way the sensor will need to be replaced for the ECU to function properly and for your CEL to go out.

Gadget

OK, the code does not tell you what is wrong. It only recommends what diagnostic proceedure to run to find out what is wrong.

The thing is that at your mileage the O2 sensor probably should be replaced anyway. The proper diagnostic work might end up being more expensive then the sensor, so you can take a stab at it and replace the sensor, like I said it is probably due anyway. If you get lucky and that is it, then you are golden.

www.URDUSA.com has some kick ass prices on O2 sensors, but we are having trouble keeping them in stock. If you want to check out the URD site and figure out what sensor you need email me directly and see if we have it in stock before you order it.

I had the same code come up on mine while I was under warranty. I went to the dealer and "the code says it is an O2 sensor" so they put in two new ones. Well, an hour later the light came back on with the same code. I went right back the dealer, "the code says it is an O2 sensor, but we are out of them and will order you two more." I asked them if they did the proper diagnostic to determine what the problem really was or just pulled the code? "The code says it is an O2 sensor."

Well I tried to remind him, the "master Toyota tech", that the code does not tell anyone what is wrong, it only recommends what proceedure to run. The guy had that same look on his face as he twisted his head to the side, just like my dog does when I tell her to do something that she does not understand.

OK, fine, thanks, bye.

I went home, got out the Factory Service Manual and followed the dignostic proceedure and traced the problem to a faulty fuel pressure regulator. It was locked fully shut and I had 80 PSI at idle.

I replaced the fuel pressure regulator, expence out of my own pocket, and it was fixed.

Then I get this card in the mail that my two new O2 sensors are at the dealer ready for pickup. Cool, I went to the dealer parts department and go my two free O2 sensors that I did not need. ˟˟˟˟˟˟ tools....

So you can roll the dice and swap out the O2 sensor, or you can do it the right way...

Gadget

MTL_4runner

Gadget, what was the exact code number you got when that happened?
I have never heard of a fuel pressure regulator bypass locking shut like that so I was curious about the circumstances.

3.4v6

i got a check engine light too, it was something about the o2 sensor and a closed loop. are the bosch sensors good or should i just stick to OEM?

Gadget

I do not remember what the codes numbers were, but it was bank 1 sensor 1 rich condition, bank 1 sensor 1 slow responce.

Remember back in the day when the TRD kits used to come with a fuel management unit that attached to the top of the fuel pressure regulator? Well it came with a section of hose that was already assembled to the fittings needed to relocate it.

It appears that something was in the section of hose and that clogged up the regulator. It appeared to be small strips of rubber that look much like the hose liner.

When I removed the fuel return hose from the regulator with the engine running there was only a drip or two of fuel coming out of the return line every few seconds. So clearly it was clogged up. I then checked the fuel pressure and it was 80 PSI at idle. I thought the gauge was backward, because as soon as I started to drive the truck, the fuel pressure when down, when it should be going up as the throttle is opened. Anyway, replacing the fuel pressure regulator fixed everything.

....No, do not use a Bosch O2 sensor. Several people have, and reported problems and ended up buying a real DENSO sensor to replace it.

Gadget

MTL_4runner

I had a feeling it might be due to some of the mods you had done but that sucks you had to replace the regulator. I would say anything is a possibility but if they don't have any mods then it is a good shot at being just the O2 sensor. I will definately file that one away as something to look for if people have similar symptoms.

I do also agree with Gadget, stick to the Denso sensors only if you can help it.