Code 430 help

[jimmythechin]

I am having a problem with my expolorer. The CEL came on and I checked it with a scan tool. It showed code 430. I reset the code and it returned in a few weeks.

Now for the details. It is a 1997 Explorer AWD, 5.0 with 146,000 miles.

I have a scan tool that can give real time reading for the O2 sensors, but I don't know what I should be looking for.

Before I go wasting money replacing parts (os sensors, plugs, cats, wires etc.) I was wondering what I should try first. I know code 430 is for cats but I was wondering what else it could be.

How do I use the scan tool to diagnose the problem? What should I look for on the O2 readings? And also which side is bank 2?

Any help would be greatly appreciated.

 

[Cobraguy]

That is a pretty rare code. It means the ecm is seeing that the driver's side cat is not doing it's job. Three main reasons: The downstream O2 sensor is inop (worn out, unplugged, damaged wires, etc), the cat itself is bad and needs to be replaced, or one heck of an exhaust leak between the two O2 sensors. This should be easy to fix.

 

[jimmythechin]

What would you recomend trying first? Should I just replace the O2 senors (they are original) and see if the problem goes away?

 

[Cobraguy]

My recommendation would be to first inspect all wiring and connectors to that sensor. Then I would see if there is a way somebody could use a scan tool and look at the datastream and see what that sensor is doing. No use throwing money at it. But I also believe O2 sensors are wear items and if you are still using the original sensors, I would replace all 4 with that many miles. I replace them at 100,000 miles regardless of any codes or not. I can show you on a scan tool how much slower responding old sensors are to new ones.

But I would really want to diagnose the problem properly.

 

[jimmythechin]

Thanks for the help.

I do have a scan tool. What should I look for while watching the o2 sensors?

 

[Cobraguy]

That's a class in itself. This is some good information:

http://www.aa1car.com/library/o2sensor.htm

Experience will show you what a good cross count looks like on a scan tool. But it should be FAST! Milliseconds. If not, it's lazy and wasting fuel and degrading performance...even if a CEL hasn't been triggered. Downstream sensors won't have the crosscounts because they don't do a thing for the fuel control. But they should give an indication of cat efficiency. I think the article will say it very well.