2003 Needs two New Cats

[bwbski26]

Hey my 2003 is throwing the code saying both bank 1 and bank 2 cats are shot. Anyone else have this problem? My 2003 has 190k on the ticker.

 

[Bismarck]

A bad ignition coil will do the same..

 

[bwbski26]

So it is the majority of the group here thinks I need to replace my o2 sensors? How much do those cost?

 

[Trunk Monkey]

Only costs a search:

https://forum.ih8mud.com/100-series-cruisers/452771-o2-sensor-question.html

 

[RobRed]

Check Amazon for the Denso's - Super good pricing.

 

[Sam Stewart]

IIRC there was a service bulletin on the 2UZ front O2s. They had a kit to replace them both.

 

[OGBeno]

IIRC there was a service bulletin on the 2UZ front O2s. They had a kit to replace them both.

Yup. But not for the LC 2UZ and LC A/F's.

TSB is for the Sequoia's.

Different part numbers.

 

[bwbski26]

Beno,
Will the O2 sensors solve my problem?

 

[chrisratz]

Beno,
Will the O2 sensors solve my problem?

I don't know if it will solve your problem, but if I was in your spot i would try replacing the 02 sensors first, its a fairly easy DIY project, theres a good step-by-step guide referenced in the thread Trunk Monkey linked above. I used the guide a few weeks ago to replace both of my forward sensors, the whole job took less than an hour, and I think the cost of the denso sensors and the special tool was about $120 or so. Hopefully this solves your problem.

FWIW the code I was getting specifically mentioned "sensor 1 bank 1" or something of the sort.

 

[scottm]

If you can get a graphing OBDII scanner you can see the outputs of your sensors. These are screenshots from analyzing my 80, the first shows sensor #2 (after the cat, bottom-right pink line) putting out a flat-line, more than one volt, which a good sensor would not do even with a bad cat. The Second is with new sensors (from cDan), showing sensor #2 wiggling around between 0 and 1 volt, normal.

In the first shot you can see sensor #1 readings are changing more slowly, fuel trim is adjusted more slowly and to more extremes, I think this is running in a limp mode. In the second shot the fuel trim is being controlled more tightly with corrections more often, and sensor #1 is more active, I think this is the computer controlling fuel trim from sensor #1 readings. Sensor #2 isn't used to control anything, just a quality control check.

 

[Sam Stewart]

Yup. But not for the LC 2UZ and LC A/F's.

TSB is for the Sequoia's.

Different part numbers.

Thanks for the correction.

 

[AimCOtaco]

What failures would generate codes on both sides at the same time? Could it be wiring or lack of sensor heat?