2003 LX470 Rehabilitation

[EastWaCruiser]

With the looming dread of the timing belt out of the way, I can get back to more entertaining projects. I put some graphite lube in the front doors, which helped the window speed significantly. I also took apart the passenger door card, because whoever had worked on it last didn’t properly align the top of the door panel with the metal lip. And so there was an excessive gap between the inside face of the glass, and the felt trim that pushes up against the window.
It’s bizarre, there are a lot of little quirks like that on this Lexus that were done weirdly incorrectly, and are extremely easy to remedy.
I also cleaned the switches with some electrical cleaner.

 

[EastWaCruiser]

My seatbelt has always been kind of finicky. I have to press it sort of hard and quickly to get it to clasp correctly. And today, the seat belt light continued to flash even with it buckled. Well, I had some electronics cleaner in my cupholder, so while I was on the go, I unbuckled my seatbelt, blasted the seatbelt opening with the cleaner I had in the cup holder, and now it functions perfectly.

 

[EastWaCruiser]

More weird fixes today. I’m actively looking for new seats because these ones are clapped, but I figured I would see if I can fix the up-and-down adjustment. There are little plastic pins that hold the switches in their sliders (not pictured) which were in the process of breaking off - preventing the switch from moving smoothly. I went ahead and cut the end of these pins cleanly off. The switches then had a little bit more slop in them, but I found that it was all held together once I put the plastic covers back on and now everything works correctly with only a little bit more noticeable play.

 

[EastWaCruiser]

I did some fun stuff today. My mini VCI cable arrived, and worked just fine with the tech stream software I downloaded here on mud.
I used it to change a couple settings, like turning off the automatic door locks. One of the most irritating things was getting out and walking around to the passenger side, only to find that the door was locked. I also turned off the automatic telescopic/tilt function, and disabled the automatic wiper blades because I like having control over them.
I was also able to program the new key I purchased! Saving $$$ is always a rush!

 

[EastWaCruiser]

I also used the software to do some diagnosing for my P0420 and p0430 codes. A healthy oxygen sensor should produce a sine wave, and alternates between about 0.1 and 0.9v.
The downstream sensors can remain a little bit flatter.
Even if I were to not have done this, I would’ve replaced the oxygen sensors first. But this at least makes me feel like I’m not throwing money at the wind. Also, as a test, I might start by replacing the sensor with the worst waveform to see if that eliminates the code. Rather than just replacing all four.

Upstream Bank 1 sensor 1 looks ok.

(Upstream) bank two sensor one had a lot of lazier waveforms. Possibly the sign of a bad sensor.

(Downstream) Bank 1, sensor 2 looks pretty good.

And finally, downstream bank 2 sensor 2 is a little wonky. I wonder if it’s because bank 2 sensor 1 is also bad?

Bank 1 Sensor 1 stayed mostly pinned lean around 0.1 V, only creeping upward occasionally and very slowly, never forming the fast, sharp switching pattern it should. Bank 1 Sensor 2 also hovered mostly lean in the 0.06–0.20 V range, with only small, brief bumps upward and long stretches of flatness, never settling into the stable mid‑range plateau expected after a healthy cat. Bank 2 Sensor 1 showed a loose, slightly sluggish waveform, but it did switch between roughly 0.1–0.8 V, forming an irregular but recognizable upstream pattern. Bank 2 Sensor 2 spent most of its time lean as well, oscillating between 0.08–0.25 V with occasional jumps toward 0.55–0.60 V, then drifting back down, never holding a steady mid‑voltage the way a good downstream sensor should.

 

[EastWaCruiser]

This is the cable that I ordered. About $20 off of AliExpress iis hard to beat. It came with a DVD that has some software on it, which I did not use and cannot speak for.
IT SHOULD BE SAID that any kind of seedy software and hardware that you order from overseas should be plugged into a computer you don’t care about, is not connected to the Internet, and hopefully doesn’t have your own sensitive information on it.

I just found this on AliExpress: $28.55 | FTDI FT232RL Mini Vci For Toyota TIS Techstream V18.00.008 Minivci MINI-VCI J2534 Auto Scanner OBD OBD2 Car Diagnostics Cable

https://a.aliexpress.com/_mr7lQ5T

 

[EastWaCruiser]

Interestingly, I also got a couple other codes. P0113 and 102. I suppose that if the MAF or IAT sensors are reading incorrectly, then the fuel trim might not be spot on which could affect my O2 sensors.
I will investigate any easy fixes there before I start working on a “downstream” problem

 

[EastWaCruiser]

(Rainbow) Here are the numbers for my long and short field trims, number one and two for both, my mass airflow sensor, and intake air temperature. They’re all within spec. I noticed the engine changed its tune a little bit when I wiggled the maf plug. It sounds a little smoother now. I may just clean it with some mass airflow sensor cleaner, and ensure that it has a solid connection, clear the codes, and move on. I will re-address it if the code returns.

 

[EastWaCruiser]

Replaced the upstream O2 sensors, as well as the radiator today, as the old one had developed a leak. It looked like it had been replaced in the past with an off brand unit. The late owners of this rig were incredibly cheap…
After clearing the codes, P0 420 and P0 430 came back. I will have to continue to look into that.

 

[2001LC]

Very often a P0430 & P0420 are bad CAT(s). But sometimes just dirty.
That fact, its on second radiator, is not a good sign. Why: Coolant issues are red flags. Of possible head gasket leak, form over heating.

I'd:
You can also run borescope, into O2 ports and look at CATs. See if burnt up.

Study head gasket externally.

Then a compression test, in hot engine. Then, before re- installing spark plugs, let cool down over night. Pressurize coolant system to 15LB to 20PSI, in cold engine. Use bore scope and inspect head gasket in each cylinder, for coolant drips. Once done, install plugs. Keep or install pressure gauge on radiator and set to15to 17PSI. Warm engine, to about 140 to 170F. Shut down. Set pressure at 15PSI. See if hold over next hour or two. You can set up gauge on rad, pre engine warm up pulling spark plugs for compression test. But you may build to much pressure in coolant system, and blow off hoses or worst.

If CATs not burnt up. Once engine full tuned-up and has good oil. Run a can of Cataclean or Sledge hammer in gas. Then do High RPM (cook off) runs afterwards, at ~4,500 RPM. You can run at higher RPM, but CAT will max at about 4,500 RPM. Run on HWY for ~2 min's. in low gear to get 4,500 RPM, the shift back to D and cruiser for awhile to cool CATs. Then 3-5 min's cook, then cool. Then 7-10 min's or more to cook. Like turning oven to self clean!

 

[EastWaCruiser]

Very often a P0430 & P0420 are bad CAT(s). But sometimes just dirty.
That fact, its on second radiator, is not a good sign. Why: Coolant issues are red flags. Of possible head gasket leak, form over heating.

I'd:
You can also run borescope, into O2 ports and look at CATs. See if burnt up.

Study head gasket externally.

Then a compression test, in hot engine. Then, before re- installing spark plugs, let cool down over night. Pressurize coolant system to 15LB to 20PSI, in cold engine. Use bore scope and inspect head gasket in each cylinder, for coolant drips. Once done, install plugs. Keep or install pressure gauge on radiator and set to15to 17PSI. Warm engine, to about 140 to 170F. Shut down. Set pressure at 15PSI. See if hold over next hour or two. You can set up gauge on rad, pre engine warm up pulling spark plugs for compression test. But you may build to much pressure in coolant system, and blow off hoses or worst.

If CATs not burnt up. Once engine full tuned-up and has good oil. Run a can of Cataclean or Sledge hammer in gas. Then do High RPM (cook off) runs afterwards, at ~4,500 RPM. You can run at higher RPM, but CAT will max at about 4,500 RPM. Run on HWY for ~2 min's. in low gear to get 4,500 RPM, the shift back to D and cruiser for awhile to cool CATs. Then 3-5 min's cook, then cool. Then 7-10 min's or more to cook. Like turning oven to self clean!

Failing head gasket is an interesting theory. My gut tells me it’s unlikely just due to it not displaying any other signs of a failing head gasket. There was a leak I could visualize at the bottom of the radiator. but worth looking into for sure. It has a fairly consistent dealership service history with no specific mention of the head gasket. I did see quite a while back that the dealer recommended a new radiator, but the “customer declined”, and then came back not long after with a replacement radiator so they probably did it themselves with the cheaper unit that I just removed.

But compression tests are easy and good peace of mind.