My engeine light is on and I'm getting a "PO420" code. ??

"P0420 Catalyst System Efficiency Below Threshold (Bank 1)".

Has anyone ever delt with this code before. Wiil it hurt the motor to continue to drive it.?

Thanks for te replies.

 

how many miles on the truck? heres the thing, assuming thats the only code, that code can be cause by a misfire, worn spark plugs, bad oxygen sensor(s), and usually the cats themselves(at least that i've seen). has the truck ever been tuned up? and within how many miles? whether its missing or not worn spark plugs can actually cause catalyst efficiency codes. as far as the rest of the possibilities go, the dealer will have to actually diagnose the problem- they'd have to look at a few sensors and things to verify its the cats. if its the cats and its got less than 80000 miles on the truck then it'll be covered under emmisions warranty.
as far as driving it goes, usually as long as you didnt notice a power loss then its safe to drive, if there is a power loss then the cats are most likely restricted..

 

I agree, -good post Matt. Usually the converter on that side (pass) or a leak.

 

Wait lol, bad O2's will not set that DTC with these engines, -ie, preventative programing.

 

no? sorry, i seen it happen a few times on jeeps and gm products i figure fords would still have that possibility.

 

According to the Ford program, faulty HO2S sensors do not produce the DTCs P0420 and P0430. The sensors must all be tested and shown to be reliable before the Catalyst Monitor can be called by the Executive.

I've never seen anything to prove otherwise. Not yet anyway..

 

Thanks for the replies.

It has 105000 mi. I just had the plugs changed a week ago when I had an injector go out and cause a missfire.I picked up the truck 6 months ago the guy had a 5 star tuner on it,after a month I put it back to stock.There is no power loss. I turned the engine light off yesterday and it has not come back on yet.?

 

Yea it will most likely be back after about 3 d-cycles or so. Per D Cycle, the switch rate of the rear sensors is compared to the switch on the front. It follows that if the catalyst is efficient it will be removing HC and HO and the rear sensor will show a slow switch rate compared with the front. By dividing the number of downstream switches with those of the upstream gives a catalyst switch ratio, and a typical threshold is 75%, above which a DTC will be recorded.

That's what needs to failed three times before the MIL light will switched on. If your converters are marginal, it may take a few more drive cycles to kick the MIL back on.

 

Thanks jbrew.

So do I risk damaging the motor if I continue to drive it.?

 

NP.

Nah, - you won't hurt it.

 

You may want to take it to a muffler shop and get the backpressure tested, just in case the cat is starting to plug up. Misfiring is hard on cats.

 

Right, - if a misfire occurs, the unburned fuel and air mixture is pumped by the exhaust stoke into the catalyst, where it washes over the advanced coating on the catalyst honeycomb. The next blast of hot gas then ignites the mixture, driving up the catalyst temperature by as much as 800ēC and causing a marked deterioration in the catalyst, so that severe catalyst damage can occur very quickly.
It is for this reason that the Fuel rail turns off after only four seconds on starting if the engine has not fired - it prevents unburned fuel being pumped into the exhaust.

 

hello guys am very frutrated i bought my truck a year ago well it had a bad miss so i replace the plugs with e-3 new belden wires from napa ck the code and it was p0420 so i replace the o2 down stream cause it was flat line but the code came back so i left it like that then i notice that the right cats were making noise so i just replaced them with high flow cats both down streams cause they were falling apart inside now ive done all this just resently and i still have that stupid code the truck runs great more power from the high flow but im out of answer can some body guide me here please and thank you for your help in advance.

 

Absolutely no punctuation.

Very disrespectful. You want us to give you the time of day, -post something legible.

 

couldnttellifyouresetthecodebutyouneedtoresetthepc mandcheckforexhaustleaksaroundthatcatalystsensor.