98 Ford Explorer fault code: P0430 Catalyst Effeciency below threshold (banks 1&2)

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Author	Topic: 98 Ford Explorer fault code: P0430 Catalyst Effeciency below threshold (banks 1&2)
janunez Junior Member	posted 06-12-2003 12:02 PM 98 Ford Explorer fault code: P0430 Catalyst Effeciency below threshold (banks 1&2). I have a 98 Ford Explorer, automatic, 5.0 V8 with 78k that failed emissions due to codes P0420 and P0430. I replaced the sparkplugs for good measure and reset the computer by removing the neg. cable from the battery terminal. Check engine light went out but came back after about 100 driven miles. The truck runs and idles very smooth and has good power, however the MPG have dropped according to the display console, from about 15.7 to about 13.5. I have done some research on what the codes mean but the causes are too general for me: Malfunctioning ECT/CHT, High fuel pressure, Damaged exhaust manifold, Cylinder misfiring, HO2S wiring concerns (shorted or chafed, bent pins, etc.), Damaged exhaust system pipe, Damaged muffler/tailpipe assembly, Retarded spark timing, Damaged Catalytic Converter: Use of leaded fuel, Oil contamination/consumption, Silicone contamination (sealants/cleaners). Anything you can suggest would be greatly appreciated. IP: Logged
wcaseym Junior Member	posted 06-12-2003 04:55 PM I am no expert on Fords, ... so consider this as a generic answer only, but for starters I suggest following checks: Check first for exhaust leaks - section of exhaust before three-way catalyst. Second, check for air leaks in air inlet system - section after the air mass flow sensor. Third, ... check wiring harness to fuel injectors. Fourth, ... check injectors that these do not drip fuel with ignition on-engine not running. Finally, check that all wiring connectors to the computer are OK. If all above stands up to specifications, ... I say you most likely need to replace your catalytic converter. C. IP: Logged
biggie44 Junior Member	posted 07-17-2004 12:10 AM quote: Originally posted by janunez: 98 Ford Explorer fault code: P0430 Catalyst Effeciency below threshold (banks 1&2). I have a 98 Ford Explorer, automatic, 5.0 V8 with 78k that failed emissions due to codes P0420 and P0430. I replaced the sparkplugs for good measure and reset the computer by removing the neg. cable from the battery terminal. Check engine light went out but came back after about 100 driven miles. The truck runs and idles very smooth and has good power, however the MPG have dropped according to the display console, from about 15.7 to about 13.5. I have done some research on what the codes mean but the causes are too general for me: Malfunctioning ECT/CHT, High fuel pressure, Damaged exhaust manifold, Cylinder misfiring, HO2S wiring concerns (shorted or chafed, bent pins, etc.), Damaged exhaust system pipe, Damaged muffler/tailpipe assembly, Retarded spark timing, Damaged Catalytic Converter: Use of leaded fuel, Oil contamination/consumption, Silicone contamination (sealants/cleaners). Anything you can suggest would be greatly appreciated. IP: Logged
mnsweeps Junior Member	posted 07-17-2004 11:40 AM quote: Originally posted by janunez: 98 Ford Explorer fault code: P0430 Catalyst Effeciency below threshold (banks 1&2). I have a 98 Ford Explorer, automatic, 5.0 V8 with 78k that failed emissions due to codes P0420 and P0430. I replaced the sparkplugs for good measure and reset the computer by removing the neg. cable from the battery terminal. Check engine light went out but came back after about 100 driven miles. The truck runs and idles very smooth and has good power, however the MPG have dropped according to the display console, from about 15.7 to about 13.5. I have done some research on what the codes mean but the causes are too general for me: Malfunctioning ECT/CHT, High fuel pressure, Damaged exhaust manifold, Cylinder misfiring, HO2S wiring concerns (shorted or chafed, bent pins, etc.), Damaged exhaust system pipe, Damaged muffler/tailpipe assembly, Retarded spark timing, Damaged Catalytic Converter: Use of leaded fuel, Oil contamination/consumption, Silicone contamination (sealants/cleaners). Anything you can suggest would be greatly appreciated. I recently had P0420 on my 99 Camry and had to replace the two O2 sensors ( air fuel ratio sensor in CA) and the catalytic convertor. The CAT was under warranty but had to shell over $440 for the sensors and labor at Toy dealer. The first time it i had 5 error codes. 2 P0420 and 3 misfires (P0300,301,302). I did a major maintanence ( which replaced plugs and wires ) and that stopped the misfires. I have a feeling the misfires somehow damaged the sensors and cat in first place.. IP: Logged
BMasterjerry Member	posted 07-18-2004 11:50 AM Ford states that a P0420/P0430 can not be caused by the O2 sensors. Make sure that your air/fuel filters are OK and the engine is getting up to proper operating temperature. Your computer has an "adaptive stratagy" that actually "learns" the driver's driving habits including transmission shift points, etc. so when you cleared the codes by unhooking the battery,it went back to a relearning mode which might account for your fuel mileage drop. Finally, as stated in many threads before, most Cats are covered 8 years/80K miles under emissions warranty... [This message has been edited by BMasterjerry (edited 07-18-2004).] IP: Logged
mnsweeps Junior Member	posted 07-19-2004 12:17 AM quote: Originally posted by BMasterjerry: Ford states that a P0420/P0430 [b]can not be caused by the O2 sensors. [/B] Can you please provide a official link to this Ford statement ? Thanks IP: Logged
BMasterjerry Member	posted 07-19-2004 07:24 AM ...Sure, but you have to be a registered dealership employee to access the site. http://www.qcdealer.com It comes up in a SSM (Special Service Message) whenever running OASIS for MIL concerns... IP: Logged
carfixer Member	posted 07-19-2004 08:38 AM quote: Originally posted by mnsweeps: Can you please provide a official link to this Ford statement ? Thanks BMasterjerry is correct. The O2 sensors will not set this code. The misconception is this... since the PCM uses the O2 sensor to monitor catalyst condition, then a bad O2 sensor could set this code. A bad O2 sensor will cause a different code to set. IP: Logged
mnsweeps Junior Member	posted 07-19-2004 10:17 AM quote: Originally posted by BMasterjerry: ...Sure, but you have to be a registered dealership employee to access the site. http://www.qcdealer.com It comes up in a SSM (Special Service Message) whenever running OASIS for MIL concerns... Is this true only for FORD? My 99 Camry had the code P0420 set and teh dealer recommended changing the two O2 sensors and I had to shell out $440 for the 2 sensors. The CAT was replaced under warranty. Did the dealer cheat me? If so I want an official note which I can print and throw it on his face as proof of his duping me. IP: Logged
gbrand Member	posted 07-21-2004 07:30 AM I respectfully disagree with the statement that 0420/0430 cannot be caused by oxygen sensors. Theory-the cat's job is to "burn" unburned/partially burned byproducts of combustion. So ther should be much less free oxygen coming out of the cat then going in as the oxygen is consumed in the cat. Since OBD2 the cat is monitored for this difference in oxygen levels by the oxygen sensors. This is why the second post cat oxygen sensor was added to cars. Case in point- On a Subaru BBS I subscribe to, a member complained he was getting a 0420 code and his dealer told him he needed a cat for 800 some bucks, and he asked the BBS for a second opinion. I explained the about theory, and asked him to perhaps get the Oxygen sensors checked first before spending that kind of money. he took the info back to the dealer, and confronted the dealer, who found out there had been a TSB or recall on the post cat Oxygen sensor on that model, replaced it for free and the code went away. I am NOT saying this is your problem, but my OPINION is that a defective oxygen sensor CAN produce a defective cat code when in fact the cat may be fine. IP: Logged
BMasterjerry Member	posted 07-23-2004 11:03 PM quote: Originally posted by gbrand: I am NOT saying this is your problem, but my OPINION is that a defective oxygen sensor CAN produce a defective cat code when in fact the cat may be fine. My opinion? I would completely agree with you. I think that logically, if the computer is watching switching rate (long or slow) on the catalysts, how could a defective sensor not be a possibility? I'm just repeating Ford's statements and actions that I've personally witnessed when working @ a Ford Dealership. Ford will "backflag" (charge back the complete repair to the dealer) any warranty repair where the post sensor was replaced for either code. They claim it will ONLY throw the code if the sensor is properly working... IP: Logged
carfixer Member	posted 07-24-2004 11:06 AM quote: Originally posted by gbrand: I respectfully disagree with the statement that 0420/0430 cannot be caused by oxygen sensors. Theory-the cat's job is to "burn" unburned/partially burned byproducts of combustion. So ther should be much less free oxygen coming out of the cat then going in as the oxygen is consumed in the cat. Since OBD2 the cat is monitored for this difference in oxygen levels by the oxygen sensors. This is why the second post cat oxygen sensor was added to cars. Case in point- On a Subaru BBS I subscribe to, a member complained he was getting a 0420 code and his dealer told him he needed a cat for 800 some bucks, and he asked the BBS for a second opinion. I explained the about theory, and asked him to perhaps get the Oxygen sensors checked first before spending that kind of money. he took the info back to the dealer, and confronted the dealer, who found out there had been a TSB or recall on the post cat Oxygen sensor on that model, replaced it for free and the code went away. I am NOT saying this is your problem, but my OPINION is that a defective oxygen sensor CAN produce a defective cat code when in fact the cat may be fine. GM also black flags O2 sensors on warrantee repair if the code was for the cat. They state the same thing that Ford does. I happen to know this is the way GM uses the PCM logic and Paul Blastius [sp], who is a Ford engineer, states on iATN that Ford PCM logic works this way also. The logic......prior to setting a code the PCM will fatten and or lean out the mix and watch for expected changes. If the O2's respond accordingly and yet the rear O2 is switching at a rate that meets a particular threshold as compared to the front under stoichometric conditions the PCM will rightfully set the cat code. If either of the O2's fail the fatten and or lean test the PCM rightfully sets the corresponding O2 code. This is a greatly abbreviated description. The vehicle has to meet certain driving conditions before the PCM will run the logical test. These conditions may vary between vehicular platforms but the test results will point to the proper place of failure. For more information you can go to iATN and do a search of the technical theory forum using O2 sensors and catalysts codes as the subject. There's much good info in there. To do searches requires a basic membership of $10 a month. Well worth it to anyone who works with OBDII on a regular basis. http://www.iatn.net By far the largest wealth of overall OBDII information found anywhere on the web. iATN also has the largest database of real world fixes for automotive related problems across all platforms. [This message has been edited by carfixer (edited 07-24-2004).] IP: Logged
RainY Junior Member	posted 07-29-2004 04:53 PM wait, i m confused, so the bad O2 sensors will give u P0420 code? or the bad Cat? what if the car is honda with 103xxx mileage on it and still using the OEM sensor? bad O2 sensor or cat? IP: Logged
gbrand Member	posted 07-29-2004 10:43 PM First, back to basics. The 0420 code means the cat is not operating as well as it should, HOWEVER, in some cases this can be caused by defective O2 sensors, and your cat is fine. Having read your other post, the rough running you had on your car may have damaged the cat and /or the O2 sensors, really you should find out what caused that and fix it if possible. Or the 0420 code could have been set set during this time. You may want to try to clear the codes and re-run through the driving cyle to see if the 0420 comes up again, but all the "freeze frame" data will be erased from the time of failure so if you are thinking of taking it to a shop DONT clear the codes. I will post more on my running battle with an intermittent P0172 and P0420 code that NO ONE, including the dealer, the state certified emmissions shops, or any BBS can figure out. IP: Logged
carfixer Member	posted 07-30-2004 08:26 AM quote: Originally posted by gbrand: I will post more on my running battle with an intermittent P0172 and P0420 code that NO ONE, including the dealer, the state certified emmissions shops, or any BBS can figure out. Where's this request posted? I would like to see what you started with, what you've done, and where you're at right now. IP: Logged
gbrand Member	posted 07-30-2004 12:01 PM here are two old posts describing some of my issues: http://www.obdii.com/ubb/Forum1/HTML/001174.html http://www.obdii.com/ubb/Forum1/HTML/001251.html After getting the car back from the dealer, I just said let things be for a while. When it came time near for inspection, I rotated the oxygen sensors to see if that made a difference, and at one point it became disconnected. After setling in on one of the new ones, and clearing the codes, I drove the car until all the monitors set and got the car inspected . Several weeks later the 0420 code came back, and I did nothing. Over Xmas I had a very intermittent miss, tryed many things but finally found the root cause as the coil housing. Just recently my battery blew up(literally), and I replaced it, of course during the time it was disconnected the ECU reset and the MIL light went out. Then a week later it came on, and had been set by a 0172 code. The MIL went out, but still shows a pending 0172 code now for several weeks. The cat monitor has not been set yet, but I will prolly have to deliberatly take it thru a driving cycle to complete as I did before. Will post on the results. IP: Logged
BMasterjerry Member	posted 08-07-2004 12:40 AM Your problem consists of 2 codes (P0172/P0420) in which one (P0172 running lean) could effect the other (P0420 Cat effeciency). The Ford statement is for stand alone Cat effec. codes P0420/P0430. If your Subaru friend's replacement on the post-cat O2 really fixed the P0420 (only code?) I will add it to my future responses as a possibility... IP: Logged
geo Junior Member	posted 08-29-2004 05:24 PM replace cat and o2's IP: Logged
mjfeeney Junior Member	posted 09-05-2004 07:05 AM Quote: replace cat and o2's After reading this, I disagree: http://www.wellsmfgcorp.com/counterpoints/counterp_v7_i3_2003.pdf http://www.wellsmfgcorp.com/counterpoints/counterp_v7_i4_2003.pdf IP: Logged
asndad1948 Junior Member	posted 09-05-2004 08:35 PM try checking the wire harness for broken wires. My Escape had a code set, I replaced the corrisponding parts, only to fire a braken wire. the insulation was good, but the wire inside was broken causing other problems. IP: Logged

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