Little GX help please? Yes I know, wrong forum. (1 Viewer)

[CloudCity]

So I always get responses in the 100-series forum almost immediately but my post in the GX forum regarding my bud's rig hasn't gotten any replies at all. I'm trying to figure this out today so I can get parts ordered by the weekend to get him fixed up if it's something as simple as O2 sensors, etc.
I'm curious how much carry over there is between the GX470 and our 100-series and if anyone here can offer some help?

Original post is in the GX forum here: 2009 GX470 O2 sensor/catalytic converter question

Thanks much, definitely makes me appreciate the 100 group!

 

[ibrahim83]

try this,
drive the car until you have a quarter tank or so left. Dump a whole bottle of seafoam in your gas tank. Get on a freeway and keep it in 4th if you have a 5 speed, or 3rd if you have a 4 speed, keeping revs to around 4k. Do that for about 10 miles. keep driving until you get as close as you can to empty.

refill tank, erase code, and you should be good. i've done it on two different 100's with success.

 

[Madbodhi]

I used BG 44K fuel system cleaner and it took care of the issue.

 

[2001LC]

I'm working on a P0420 now. I saw nothing indicting I bad A/F or O2. I ran 44K and did the Italiano burn out (high RMP on HWY), Then a can of CATACLEAN and Italiano. The pulled A/F sensor and ran in a drain snake camera into CAT, and looks like CAT clogged. Sprayed sea foam directly in through A/F sensor hole onto CAT while idling and then did a Italiano run. P0420 just keeps coming back. I'm replacing CAT since A/F and O2s readings seem Okay.

Many have had luck with replacing forward sensor (O2 or A/F) in these cases. If replace O2 or A/F takes care of it great They do go bad. But if bad CAT look for why it went bad and correct up stream issue causing is key to job lasting.

BTW: P0420 is bank 1 (driver side) CAT. Sensor 1 is front or forward sensor. They are O2 in non VVT and A/F in VVt engines (May 05-)


Image a little deceptive, as light makes it looks like just one small area is open or a hole through the clog. But it seems to be more of a clog around outer area and inside the CAT.

After direct spray of sea foam fogger. Seems it cleared clog a little, but not enough. P0420 came back every time.

 

[white_lx]

Like the 100 series, the 120 series GX have problems with exhaust manifolds cracking. Once the crack gets larger there could be air entering the manifold before the location of the B1S1 sensor - potentially resulting in a P0420. Do you notice the ticking/hissing sound from the manifold with a cold start-up?

You were also asking about the sensors reading 0.0V? The BxS1 sensors are A/F sensors, and you will need a good scan tool to read the output. A generic one, might not read correctly. Under normal conditions, the A/F output should be around 3.3V.

The catalytic converter and exhaust manifold are a single part on the GX. So, if you go about replacing it, you will need exhaust manifold gasket and the round gasket on the other side and some extra studs and nuts.

I found very little information about the actual replacement process, but the videos below were useful when I replaced the manifold/converter on a '08 GX (videos are for a 4R, but same engine/manifold).

Instead of loosening the air bypass pipe, I removed the two little studs from the manifold and put the studs back in after the manifold was in place. That way you don't have find the invisible 10mm screws on the vacuum valves. I also needed to lift the engine about 2". Only loosened the driver side engine mount.

 

[CloudCity]

Thanks to all, I am thinking it's an O2 sensor as it hasn't reappered since clearing, and since I just did the upstream bank 1 on my LX I am familiar with the operation if need be. I'll update if it comes back and I find a resolution.