I've got an '02 4runner 3.4 5vzfe with Cali. emissions.

My REAR catalytic convertor was stolen a few weeks back. It was unbolted between the muffler and front cat. The O2 sensor wires were cut in front of the connector.

So, I replaced the cat with a unit from Eastern Catalytic. Part number 40353. This is supposedly a direct-fit OEM cat for my vehicle. I asked repeatedly, and was assured repeatedly, that this unit would in fact work with a california emissions system, and that it was in fact CARB certified.

I went to a dealership to locate a new O2 sensor to replace the one stolen. When calling up the part number, their computer showed a different O2 sensor than what I needed. Their computer pulled up a universal-fit O2 that screws into a bung. Mine requires a flange with 2 bolts.

So, I had them look up an O2 sensor from a tacoma of the same year with the same engine. This brought up an O2 sensor part number 89465-09340, which is a POST-Cat O2 sensor for a Tacoma. Cross-referencing that part number, we found it for a 4runner as well. So both the tech at the dealership and myself were confident this would work. The Tech had said the post-cat O2 sensor does not matter regarding Cali-emissions, and that they are all the same. Unfortunately, I did not have my VIN at the time to double check against with the part numbers. If anyone HAS a post-cat O2 sensor part number for an 2002 4runner v6 with Cali-emissions, that would be awesome if you'd post it

I had to splice my connector back, as the crackhead who cut it out didn't know where to cut it, and actually had to cut twice. So luckly, I still had my original connector. I simply had to rewire it back together, and then plug in my new O2 sensor.

After about 2 days of driving, my CEL came on, and is throwing a P0136 code, which is a post-cat O2 sensor code.

My questions are:

Can anyone confirm that I have the correct O2 sensor?
Can anyone confirm that I have the correct Catalytic Converter?
Is there supposed to be a gasket between the O2 sensor flange and Cat flange?? Mine did not come with one.
Would this code indicate a LEAK in the cat or the flanges?
Is it possible I have a faulty O2 sensor and simply need to replace with a new one?
Is it in any way possible at all to screw up splicing wires together?? I mean, I'd like to think I'm not totally incompetent when it comes to things like this

I DO plan to call the dealership with my VIN in hand to make sure I've got the correct part, but any additional help would be greatly appreciated.

Thanks.

 

The code would indicate it might not be the right part number. Have them run the VIN at the dealer to be sure you're getting the correct part. You may need to have a bung welded onto the new pipe if it doesn't have the correct mating for the stock sensor.

According to the 02 FSM P0136:

Open or short in oxygen sensor circuit

Heated oxygen sensor

Heated oxygen sensor heater

So either it is the wrong sensor or you have a problem with the sensor heater wiring.


Just an FYI but when the code refers to an O2 or air/fuel sensor:

If it has P01XX = it is an O2 type sensor
If it has P11XX = it is an A/F type sensor

Just makes getting parts easier when you know what your looking for.

 

o2 sensors deal with low amps and low volts on the signal side

and the heater circuit which is big amps

perhaps the splice isn't electrically efficient, and it is slightly off spec due to the splice job, and you'd be better
off resoldering it again, or getting the whole thing from toyota
with new connector.


also....the rear 02 sensors job is to measure how much the cats are doing to the exhaust.
that aftermarket cat may not be up to snuff. even with a guarantee that it will work, it doesn't
carry the same weight as the identical cat that the ECU was programmed for.