PO131.....2004 year. Just for ideas from Tacoma owners

I'll start by saying this is not on a Tacoma but a Lexus, I'm sure the system is very similar between year models between the two though. Sorry not to post in "Others" but this has the most traffic and it is a Toyota and this should translate over for future Taco owners with V6's.

Got the code a a while back and had trouble with my OBD reader getting it out. Don't know why as it reads every other vehicle fine, checked all fuses and they were ok (OBD has it's own fuse and power is there as it turns off my reader and back on when fuse put back in.) Drove to AutoZone and they were able to pull it easily....131. I disconnected battery and as soon as I cleared it and restarted, it popped right back on.

They don't have a live readout though so i took a chance and ordered a Denso sensor (bank 1 sensor 1 upstream) and replaced. Code gone. Didn't drive much, just restarted a few times and let warm up for 30 minutes each time.

Well last week i went to start it and the light came back on, still no reading with my reader (I'm suspecting this may hold a clue) but back to AZone and sure enough 131. Disconnected battery again (AZ will not turn one off so I have to start over with 'ready' monitors every time I do this)

I can find no short in any wiring I can get to esp. around exhaust where it may have burned and sure see no exhaust leak. Exhaust is in really good shape @ 150K miles

Any ideas where to check next? I really don't have the money (right now) to go buy a better, newer reader (some day I want a live read).

This particular vehicle is hard to get probes into the harness to check for fluctuating .04V-1.00V output on that sensor. It's up in bad spot and harness is covered as soon as sensor is installed.

 

I think I may look at plugs today just for giggles.

 

What kind of Lexus?

 

LS430, small V8, similar to the 4.6 of the Tundra.


Sorry, I thought I had put in the model/year.

it's a 2004 Lexus LS430 with 4.3 V8. Runs fine with light out, limp mode with light on.

It's not so much the check engine light that's bothersome, it diables the VSC when it recognizes the sensor and lights the whole dash like a Christmas tree. Exclamation marks and beeps. No codes come back from that system, it's just part of the 'limp'.

 

I am guessing your reader and the plug on the car have a poor connection on one or more of the pins

Causing your frustration

You might also want to look at the pigtail where the sensor plugs in

 

Try disconnecting the battery?

 

I think the car could use a new set of spark plugs (original iridiums) but when I told her how much she balked.

I should have also mentioned I had removed the pigtail and cleaned it and the reader. It connects and powers up but reads 'link error' when trying to read.
Funny thing is the pin pattern isn't standard to Toyota and doesn't even match what i can pull up on the internet for the specific car, yet Auto Zone can read it.

Yes, that's how I cleared it.


moderator can this thread be moved to 'other vehicles' in Off topic?

 

did you replace the right sensor?

https://www.clublexus.com/forums/ls...ygen-o2-sensor-location-and-part-numbers.html

I dont know if this applies to your vehicle but I read one on a GX and it kicked that code for this part.

$81 Dorman 911-907 Engine Intake Manifold Runner Control Valve Compatible with Select Ford / Mazda / Mercury Models

https://www.amazon.com/DORMAN-911-907-Intake-Manifold-Control/dp/B00GJ1G72Y

 

https://lexusforum.com/forum/lexus-ls-9/faulty-o2-sensor-ls430-397/

Looks like a cleaning of the MAF sensor and 'fixing a leaky gasket' is what this guy states fixed his recurring P0131. He had tried replacing 02 sensors multiple times.
Not saying it'll fix your issue, but it could give you an idea is all.

 

As similar as the car engine is to the truck, the car doesn't use that particular part. I had to look up the engine just now as i always wondered why they produced a 4.3 and a 4.6 V8 during the same years. Car engine has aluminum block, truck does not. Both have the damn air pump that breaks though unfortunately.

I will give that a try as I have some spray here already. Seems like all kinds of things can cause fluctuations to that circuit. I'm betting those are original plugs and they are the culprit. Trying to talk her into buying a set but if the light comes back on again after that, well you know. I'll never be trusted again.

Still trying to sort out why my scanner won't interface and it does on both of my Toyotas. I realize that if nothing is plugged into it, it shouldn't have any bearing on throwing a code.

I appreciate the tips, gives some things to looks at. I imagine besides a short somewhere (unlikely, although 131 vs. 31 is the heater to the sensor) it has to be one of these things.

Since most of the Toyota problems I see nowadays are emission related I really need a live data reader before something like this pops up on my own vehicles. This is why I say "the older the better" as far as OBDII.