AgRunner06

I just pulled the codes on the '96 LC with my little $40 code reader (which by the way worked great). Here's what I came up with:

0401 EGR flow insufficient detected
0402 EGR flow excessive detected
0420 Catalyst system efficiency below threshold (bank 1)

I'm not too sure about the EGR. The EGR valve and modulator have both already been replaced. Is there a sensor somewhere that I can easily replace? I do know that there is a VSV but would this cause both codes?

Could the 0420 code be a 02 sensor problem? I think the LC has about 165K miles on her and I bet she could use an 02 sensor.

Let me know what you guys think.

Thanks

:bounce2:

blupaddler

Ahhh, EGR...

Yes there is a sensor next to the modulator, I think. Although my 1994 is probably different than yours.

Also check out www.ih8mud.com and search under EGR or the code in the 80's section. I think there is even a sticky post on the subject too. EGR is a common problem.

99runner4me

I had to replace the modulator valve on my '97 not too long ago. A code on my friend's '96 says the same thing. He hasn't taken care of it yet. He's been driving around with his check engine light on for a while now. I'm assuming it's probably the same culprit.

AgRunner06

Anyone else have any ideas?

WolfpackTLC

Sorry d00d... bite the bullet.. it's definitely the EGR.

NOMIS

I have a '96 LX450 and had the same code - mine turned out to the upper O2 sensor. Bought the O2 sensor fromToyota for $130. It's easy to replace it - location is under the pax side near the wheel well - two nuts and it's off - replace the gasket which comes with the new one and you're good to go, very easy.

AgRunner06

I have also been told the upper O2 sensor by a friend of mine that works for Toyota. I think I'll give it a shot.

Thanks a lot.

:bounce2:

NOMIS

Let us know how it goes. Good Luck.

AgRunner06

I figured I'd let you guys know what I came up with.

I replaced the upper O2 sensor and reset the code. The CE light came back but only with the 0402 code. I've already replaced the EGR valve and modulator. So that leads me to believe the only thing left is the VSV. It is my understanding that this is located under the upper intake manifold. So I probably won't be replacing it.

Anyone else have any ideas?

Thanks