cha41ppy

I've been hanging around here not really saying anything so I figured I finally contribute my first post since I have some useful information to add.

Bought a 99 ES300 two months ago with 93000 miles, beautiful car, runs fantastic - until about one month ago when it began sputtering and immediately threw a CEL with codes p0171, p0300, p0302, p0304, p0306. This condition became intermittent, once every 3-5 days or so. It would sputter and shake at idle, smoke like a ****, and jerk really hard at speeds > 45 mph, blinking CEL here and there. The light was reset 3 times with the identical codes returning.

So like a dumbass I begin blindly throwing in parts. Put in NGK iridiums, no diff, new MAF sensor (only 70 bucks), no diff, Seafoamed intake, nuthin, changed oil to synthetic, new air filter, throttle body cleaning. Nothin changed except the car ran smoother when the sputtering wasn't occuring. I am suspecting Bank 2 AF ratio sensor at this point although its an expensive part and I've read people saying that this will not cause misfires.

Brought the car to Toyota, BIG mistake. They tell me I have the wrong spark plugs, they are wrong. They want to put in Denso platinums when I finally show them that it states clearly under the hood Iridium only. They cannot figure it out. I said did you check the af ratio sensors and they say yes they are fine. They recommend 1800 dollars worth of garbage service to pay their kids college tuition and I say go pound sand buddy. So I demand my 85 diagnostics fee back to no avail, I will NEVER go there again, and I will ensure that their online customers see many poor reviews all over the place.

On a hunch, I order the bank 2 AF ratio sensor from factory lexus parts for 150, best price online. I install it two weeks ago, reset the ECU and voila, car is back to new. 400 miles later and no CEL. And thanks to the tune-up I performed while troubleshooting, the car runs marvelous.

Hopefully this helps someone - I figured it would be the best way to start posting at CL. Glad to be here, excellent advice.

Lexucan

Great first post! Glad to hear that you went with your hunch...obviously it was bang-on!

And a belated welcome to CL !!

Now let's see some pics of that smoooooth running baby!

esucaris1

Here's to getting the job done yourself... Even with the blindness you spent less than what the dealer would have raped you for...
And welcome to CL...

llcoolpass

so you fixed it by replacing the 02 sensors ...

they are a normal maintenance item so yeah I would replace them and the plugs immediately if a problem like this happened.

glad you're back to normal

DRACO A5OG

Hey cha41ppy,

Just a follow up, still running strong without the CEL?

I recently got the same Codes.

Jim

Trexus

Welcome to Clublexus and congratulations on fixing the problem that lead to the CEL. I had a CEL about two months ago and I had to replace the vacuum swith valve and the CEL went away...

DRACO A5OG

Good News, what kind of Trouble Code did you get?

Trexus

Code P0441. I replaced my vacuum switch valve and a got a new gas cap and that did it...

DRACO A5OG

On my 96 ES300, I got:

P0401 replaced EGR Vacuum Modulator Valve (Could not hold Vacuum)
P0135 replaced both front and rear O2 Sensors (Bad Bank 1, Sensor 1)

CEL gone but now long crank to start COLD and got P0300, P0302, P0304 & P0306.

I do not believe our year has the A/F Ratio Sensor, just O2 Sensors. Can anyone verify?

Removed and Cleaned Throttle Body and Idle Control Valve. Also cleaned with MAF Cleaner the Mass Air Flow Meter/Sensor. Runs smoother but still Cold Start Issues. Once warm it will start up immediately.

Any thoughts?

I am leaning towards the Engine Temperature Sensor. Does anyone know the OHMs for this component?

Jim

OceanView

ok, call me a dumba$$, what is "bank 2 AF ratio sensor " ?

DRACO A5OG

OK dumba$$, (no JKD). Mr. Dumas here as well, "bank 2" is the rear set of spark plugs/manifold next to the fire wall. "AF ratio sensor" is the Air Fuel Ratio Sensor for Generation 3+ ES's. 1996 and older used O2 Sensors from what I understand and still trying to get verification.

May need to call dealer.