NovaRacer

2 days ago, My ES starts jerking slightly on the highway @ 65-70 mph when I left off the gas just a little. I have a code scanner and this is what I get.

PO420
PO446
PO171
PO125
P1133
P1153

The 420 and 446 have shown up before, but t usually goes off after a few hundred miles. I'm thinking it is a Air Fuel sensor. Which one I am not sure. I have searched this forum and have seen several of the same issues. My question is should the MAF sensor be replaced also?

Thanks for the input.

WB

Zen470

I would try cleaning your MAF sensor first. You can pick up some MAF cleaner from any auto parts store for $7. Buying a NEW maf sensor is over $200 but you can pick one up on ebay or like $50. But like I said try cleaning it first.

tomf

I had similar symptoms. At cruise speeds, with my foot lightly on the accelerator the car stuttered. My problem was the A/F sensor. Based on my limited experience, I would attempt to fix it by taking the following steps one at a time then checking for malfunctions before proceeding to the following step. Your problem is probably the MAF or the AF sensors. Hard to tell which one it is.

1) Clean the MAF
2) Replace the bank 1, sensor 1 A/F sensor. (P0171) (This would be my second step because they tend to go bad starting at about 100K miles. If you are wrong, you just replaced a part that you will eventually have to replace)
3) Replace the Bank 2, sensor 1 A/F sensor (P1153)
4) Replace the MAF

Keep in mind that for the sensor error codes to activate the CEL there have to be two cycles in a row generating an error but the vsv light should come on after one cycle and a pending code present. Also the engine has to warm up about 5 minutes before the engine starts using the data from the sensors. So you won't get a CEL or VSC light until then.

00ES300PS

Great feedback, thanks! I have a 2000 ES300 and am getting a po171, po420 after I just replaced the bank 1 and cleaned the MAF sensor. Any ideas are greatly appreciated!

tomf

P0420 could indicate a bad a/f sensor, exhaust leak or a bad catalytic converter.

1) Look for an exhaust leak.

2) Replace the Bank one, sensor two O2 sensor.

3) Replace the cat.

Here's a link on how to replace the sensor. https://www.clublexus.com/forums/rx-...sor-2-diy.html

Just to clarify. Did you replace the sensor closer to the front of the car (bank two) or the one near the firewall (bank one)?

00ES300PS

I just replaced the O2 between the firewall and the engine. I also cleaned the MAF sensor and it took a while for the light to go on. The car sounds, smells, and runs great, do you think its a cat? I just bought some Cataclean and will see if that helps. New MAF sensor is $130 but maybe worth it? Why don't they have their own code? !

tomf

Are you sure you got the right sensor, Denso part number 234-9021, for a 2000 es300.

I think it's probably the bank 1 sensor 2 O2 sensor. These cars are notorious for O2 sensor failures. You can expect them to fail anytime after 100K miles.

Of course, I may be wrong. It could be something else. But for me, after looking for obvious exhaust leaks, I'd replace the sensor. (If you are wrong, you just replaced a part that you would probably have to replace eventually) O2 sensors are a lot cheaper than a cat. On Amazon the O2 sensor you need runs about $57.

I'd be surprised if it was the MAF because of the P0420 error code. So I'd replace the O2 sensor before replacing the MAF. If you know someone with an ES you could swap MAFs and see if the problem is corrected.

00ES300PS

So, the code I was reading was an old code not cleared. The car is only reading a po420. My mechanic said I probably waited too long to replace the o2 sensor and the rich fuel mixture roasted the cat in the manifold. I ordered a new manifold with cat and am putting it in tomorrow. Learned my lesson there! I'll let you all know if it works but its makes perfect sense. Manifold is only $245 with the cat.

tomf

Looking forward to see if the new cat clears the error.

00ES300PS

Put on a new cat for the firewall side which is actually on the y-pipe unless its a CA emissions car. The code went away! The lesson, don't run your car with a O2 code too long!

tomf

Thanks for the update. Learn something new everyday.

overdubber

1999 ES300.

How many sensors does the car take for the catalytic converter system.?

What are the OEM and Denso aftermarket part 3s and prices?

Thanks.

Peter