1997 F-150 This is a follow up from Friday when I was trying to figure out wether there was some way to read the codes at home.

Engine light has been on, we went to Autozone and got the codes P0420 and P0430 which are Catalyst System Efficiency Below Limit, Bank No. 1 and bank No. 2

How do I go about correcting these codes?

Thanks Brothers

75F250ford
Kevin

 

you may want to verify this but I beleive the upstream o2 sensors are both bad. (thoses are the two on the right and left side befor the cataletic converter). They run about 59.00 a piece at Advance.

The cpu should be reset as well when you replace them, you do this by disconnecting the neg battery for ten min the re connecting it.

 

Just went through the same problem with my '97 5.4. po420 and p0430 are both bank 1 and bank 2 sensors but they are after the cats(one by tranny and one where the bank1 and bank2 pipes come together). p1131 and p1151 i believe are the upstream 02 sensor codes.... good luck!


LOUD PIPES SAVE LIVES!! !

 

P0420 and P0430 cods are NOT due to O2 sensor failure, whether upstream or downstream.

The sensors are tested for proper operation prior to running the catalyst efficiency tests.

The efficiency tests compare the switch rates of the upstream sensors to the downstream sensors and compare the ratios to pre-programmed limits. If the ratio(s) exceeds the limits, the appriate code(s) is (are) set and the MIL is commanded ON.

If you have the appropriate scanner software on a notebook with an interface cable, you can observe the O2 sensor outputs and can clearly see the downstream sensor following the upstream sensor, indicating a cat that is not functioning.

You can replace the sensors if you want to, but the codes will eventually return.

Steve

 

So then back to the original question are the cats bad?? or what is the fix ifit is not the o2 sensors. confused minds would like to know.

Lance

 

Hey guys, I also find myself in the same situation. Both p0420 and p0430 codes come up and also noticed a lack of power when i step on the pedal as well as a decrease in fuel efficiency. Can just a bad sensor cause all of this or for sure my cat converters are clogged. The expedition had similar symptoms when the EGR ports were clogged but I fixed all that.

I also noticed that I began to have problems as soon as I installed a 3 inch system dual exaust, dual Flowmaster set on the expy. Do you guys think this might have caused all of this?


1998 EXPEDITION 4.6L
129,000 MILES

 

lance,

Yes, they are no longer functioning as cats. The prescribed fix is to replace them.

REBBLE,

Perhaps the expanded cat-back system is causing both problems. Improper exhaust back pressure can cause reduced power and efficiency. However, so can clogged cats. Have them flow tested to check for restrictions.

Gutting cats is always an option if clogged. MIL eliminators will then get rid of the cat efficiency codes.

Remember, the cats and most of the rest of the emissions control system is covered by a federal 8/80 warranty, so take advantage of it if you can.

Steve

 

I beleve its time for new cats. Note if you have them replaced at an after market shop, the welding of new cats might damage the o2 sensors if one is not careful. Just a thought.

Dave P

 

75,

Just a note to your original question about a home scanner. I purchased an Autotap for my laptop. It's paid for itself many times in just the last 6 months I've had it. The only issue I have with it is that a significant amount of the information you can obtain from it is meaningless without better definitions of the functions. Unfortunately all auto manufacturers have proprietary information that is not available to the aftermarket scanner makers. To put it breifly, the scanner will provide information but you will not understand a lot of it.

 

My question is where could someone go to find the scanner software you mentioned. Is this something that is available to anyone. Can I find it on the internet? Is it free? What about the cable? Please answer these questions for me, I have a laptop and if it isnt to expensive I would purchase it.

Thanks in advance.

 

75

Check out the following link. You'll find all types of scan tool systems for your laptop, palm or standalone. Some have free software but you need to buy the cables and translator or if you are so inclined you can build your own. As I mentioned above I bought the Autotap and have been happy with it. I work on cars for freinds and family so I purchased all the available protocols. If your vehicle is the only thing you are planning to work on purchasing one protocol will be much less expensive.

http://www.troublecodes.net/technical/scaninfo.shtml

 

I bought the Alex Pepper software and interface directly from him. His website is www.obd-2.com Cost was around $125 for a single format interface.

Alex is a semi-retired engineer who helped develop the OBD-II system. Just so happens, he lives within an hour of me.

Occasionally, I have seen group buys on his setup. If you happen to find one of those, you can save a few bucks.

Steve