Code PO420

[Jesus A Rodriguez]

I just came back from the mechanic because I had a check engine light and I have been experiencing misfiring. Well I was told that P0420 code came up and I had a clogged CAT that is causing the misfiring and to replace it was going to be around $1400. Maybe he is right but something is telling me to get a second opinion. I have LS V8 04. Has anybody experienced this?

 

[lincoln_zero]

CAT's get clogged for a reason. Engine is prolly running rich. Do you have hesitation in acceleration? Also since that sensor is for detecting the air, my first opinion is your mechanic is full of hot air.

Failing coil packs (very common on LS) allow improper burns to enter the CAT. Replacing all 8 Coil Packs and perhaps the Spark plugs is a start. Then clear the code and see if it comes back.
If you have hesitation in your acceleration, Replacing the coilpacks and plugs (if they haven't been done) should resolve.
Coil packs you can get off ebay for $78 for all 8, free shipping in the U.S. and replacing it yourself is a very inexpensive fix.

As for the CAT, again its throwing a clogged code from bad burns. Hopefully after you clear the code, which you do after replacing the coil packs, the code wont return. If it does come back, the sensor could be dirty and need replacing.

Let us know if that works.

Edit: I just realized you wrote Misfire. Then you definitely have failing coil packs, and thats causing the sensor in the Cat to throw codes from improper burns being dumped into the cats.
My 05' LS is doing that right now. Same thing, same code. Gotta do my coil packs XD

 

[jjcool00]

Holy world of bad advice batman. First of all, if you're ever going to replace coils always replace the spark plugs and always do all eight/six at once. Secondly, never replace them with anything but motorcraft or you will find yourself in the same situation you're in now. Most likely, your coils became marginal either because they were old or cheap (off-brand such as ebay) and destroyed your cats over time. This happened to me so I am speaking from experience. Once I had clogged cats, I tried to change all 8 coils and plugs to motorcraft but it made no difference. You need to replace your cats. Several of us have had good experiences with aftermarket cats. Be careful and steer away from the universal ones... the ones that have positive reviews from members on the forum are Walker, Magnaflow and Eastern.

When I had P0420 it was the catalytic converter... I tried everything before replacing them as they are expensive, but no luck. I got the magnaflow cats off ebay, the seller wanted something like 350$ for both, I offered 70% and he accepted. I'll try to find the link for you if it's still available.

 

[lincoln_zero]

Holy "I dont read" batman,

I advised to replace coil packs, which he has to do regardless. I only suggest the Ebay cheaps for cost effective. He can spend $300 if he wants the best. I bought the cheaps from Ebay, 0 issues 1 year later. Oh and I didn't do my sparks when i did my coils (cuz they were done 40k ago, no point changing Iridium's early). Wanna race?
Maybe you just don't know what your doing under the hood if your packs failed early. You Do know coil packs are located in the engine bay and not the trunk right jjcool?
Also, there's a good chance its just his sensor needing replacing after he changes and clears codes. And thats from experience. Start with whats cheap, then process of elimination.

As for the rest of your post, thanks for repeating what I just told the guy =p

To the OP: If you dont know if the sparks have been done, then do Both coils and Sparks, then clear Code. That will fix misfire. Otherwise, if code returns, either sensor needs replace / clean, or the Cat as well. I start cheap, then process of elimination.

 

[LS4me]

It's coil on plug...... NOT a coil "pack". They are different animals......

 

[Jesus A Rodriguez]

This is what the the mechanic wrote. "Scanned vehicle and retrieved DTC PO420. Troubleshoot code and found clogged CAT causing misfire on bank. Customer advised if he continues to drive vehicle will damage engine." I'm going to start with the spark plugs and coils first. I'm not sure if the code is cleared. The CEL is not showing anymore. Then I might replace the O2 sensors. $1400 is too expensive right now.

 

[jjcool00]

This guy, so much fail so little time to respond... he says he bought the cheap coils and had no problems yet in his prior post he says he has clogged cats - I would steer clear from any advice this dude provides, because not only does he not read, but he clearly has no idea what he's talking about.

Back to your issue, Jesus: You don't NEED to go with OEM cats, you can actually use aftermarket ones and be fine - one of the few things you can replace on the car with aftermarket components and have no issues.

If you do change the coils, plugs and sensors - get the motorcraft parts. There was a seller on ebay recently selling all 8 motorcraft coils for about $350-$400 IIRC.

 

[lincoln_zero]

http://www.ebay.com/sch/i.html?_trk...&_nkw=lincoln+ls+coil+pack&_sacat=0&_from=R40

General search Coil Packs ^
Those are the cheaps. To the OP, very likely thats your fix. If you have 'made in china' phobia like jjcool, then get the OEM's. And DONT buy used. Always buy new.

 

[Jesus A Rodriguez]

Thanks a lot for your help guys. To lincoln_zero yes I have been experiencing hesitations on acceleration. It just does not seem as powerful. I appreciate all the help.

 

[lincoln_zero]

This guy, so much fail so little time to respond... he says he bought the cheap coils and had no problems yet in his prior post he says he has clogged cats - I would steer clear from any advice this dude provides, because not only does he not read, but he clearly has no idea what he's talking about.

My 05 LS is doing that right now. Same thing, same code. Gotta do my coil packs XD

Wow, the guy who doesn't Read is you. Seriously. Go back and read.

My 2005 Lincoln LS has current Code, and needs coil packs.
My 2002 Lincoln LS was done last year, running like a beast. Oops someone didnt read where I specified "05' LS" .. derp XD

I have TWO Lincoln LS's, which means I have TWO unreliable cars, that I have to maintain TWO per year. Hence I specified in my earlier post "05 LS" because I have TWO. If you read, you would have noticed that. I know a coil pack failure when I see one.
The Signature you see below, is my 2002 Grey Lincoln LS. Good Grief Kid.


To the OP: You're welcome. This is great place to learn about the LS, I apologize for JJcool not keeping his cool on his posts, he has a hard time locating the engine on his car =p But all jokes aside, let us know updates if things are fixed.

 

[joegr]

...I have TWO Lincoln LS's, which means I have TWO unreliable cars, that I have to maintain TWO per year. ...

An alternate experience...

I have two Lincoln LSes as well. In my case, they are two very reliable cars. (In fact, all four of my cars are reliable.) But then, I have been correctly maintaining them since new (8 and 10 years now), and I have been using quality parts and following factory procedure (such as following the waring to always replace the spark plug when replacing a COP.).

I don't know how much advice I would take on maintenance and repair from someone that concedes their own cars are unreliable!

 

[jjcool00]

I don't know how much advice I would take on maintenance and repair from someone that concedes their own cars are unreliable!

This was exactly my point. He uses aftermarket Chinese parts and then vouches for them when both of his cars have nothing but issues, but hey who am I to know any different. I've replaced my coils, plugs and cats at 61K and now at 122K I haven't had a hesitation issue yet again.

 

[lincoln_zero]

An alternate experience...

I have two Lincoln LSes as well. In my case, they are two very reliable cars. (In fact, all four of my cars are reliable.) But then, I have been correctly maintaining them since new (8 and 10 years now), and I have been using quality parts and following factory procedure (such as following the waring to always replace the spark plug when replacing a COP.).

I don't know how much advice I would take on maintenance and repair from someone that concedes their own cars are unreliable!

With all due respect JoeGR, While i do respect your 'Knowledge of cars', the LS is rated one of the worst from Ford in Consumers Reports. Your attempt to belittle me, because I openly corrected one of your favored forum poster, is sorta childish. Since you concede I don't know how to maintain a car, are you implying my advice to the OP is wrong?

Also, would you have a problem telling me the correct procedure to maintaining the following that has gone on my LS:
- Front Driver bearing
- Front Passenger bearing
- Front Driver [upper] Ball Joint
- Tie rod end
- 8 Coil packs
- Driver window motor
- Rear Driver window motor
- Co2 Sensor
- Alternator
- Clock Spring
- Front Passenger caliper
- Rear passenger caliper
- Windshield (Twice, Cracked from pressure. Fail Ford.)
- Serpentine belt

That list is from my thread: http://www.lincolnvscadillac.com/fo...be-my-last-winter&p=2037335422#post2037335422

A thread to which you never showed up to tell me these are preventable by maintenance

Sorry JoeGR, that was an ignorant comment, even from you.

 

[joegr]

...because I openly corrected one of your favored forum poster...

I wasn't aware that I had any "favored" posters. It's news to me. My response was triggered by your somewhat (in my opinion) incorrect argument with someone else that was mostly (in my opinion) correct. It was also triggered by the comment about your unreliable LSes. It certainly does seem that some have gotten lemons. It's also true that a lot on here have purchased used LSes that were abused and not taken care of. They are then shocked that a $50K car might cost a lot to properly maintain.

To me, my cars are reliable if they never leave me stranded, and the run well and every thing works. It is understood by me that sometimes repairs will have to be made and that preventive maintenance is always required to one extent or another.

- Front Driver bearing
- Front Passenger bearing
- Front Driver [upper] Ball Joint
- Tie rod end


Bad luck, random part quality problem, harsh pot hole impacts? Using bigger than 18" rims?
I've had one front wheel bearing failure (with lots of warning so that it was replaced before it was anything more than a noise problem). It happens...

- 8 Coil packs

They are not coil packs. They are COPs. There is a difference. Unfortunately, COPs are a maintenance item on the LS. They shouldn't be, but we all know that they are. Get over it. I've replaced all the COPs and plugs on both of my LSes, one at about 70K, and the other at about 85K. I did this at the first sign of misfire so that I wouldn't have to replace my cats.

- Driver window motor
- Rear Driver window motor

Odd, but I did have one window motor fail on one of my Grand Marquis once. I've had to replace a window regulator on both LSes, but I'd had some of those fail on every car I'd had. (I tend to keep cars to a fairly high mileage.) Window regulators are wear items.

- Alternator
- Clock Spring

These are wear items too. I've haven't had to replace either in either of my LSes, but I've certainly worn out alternators and clocksprings in some of my other cars.

- Front Passenger caliper
- Rear passenger caliper


Really? Why not complain about replacing brake pads and rotors too. These are wear items and your mileage will vary. Same story as before. I haven't yet worn out a caliper on either LS, but I've had calipers to stick or leak on other cars and had to replace them.

- Windshield (Twice, Cracked from pressure. Fail Ford.)


Not sure how that's Ford's fault. I've had both windshields replaced due to rocks hitting them. My insurance fully paid for it. Several years ago (on another car), I went through about four windshields in a year. Finally, I insisted on using a different company to replace the fourth one (the insurance did by then too). The guy that replaced the first one had left a piece of glass down in the calking and the other people missed it too. I guess that for Ford's fault?

- Serpentine belt

Really? That's scheduled maintenance. Check at 100K miles and replace by 150K miles. I've replaced mine when doing cooling system work, so they only made it half as long. However, the ones I replaced still looked really good and I think I could have reused them. Being interested in keeping things reliable, I didn't. It used to be that you were doing good to get 30K miles out of a belt.

 

[lincoln_zero]

I wasn't aware that I had any "favored" posters. It's news to me. My response was triggered by your somewhat (in my opinion) incorrect argument with someone else that was mostly (in my opinion) correct. It was also triggered by the comment about your unreliable LSes. It certainly does seem that some have gotten lemons. It's also true that a lot on here have purchased used LSes that were abused and not taken care of. They are then shocked that a $50K car might cost a lot to properly maintain.
.

Honestly, I know alot of people on here don't like Consumers Reports, but the LS ($38,000) is much more unreliable than alot of other cars which are classified as Luxury Sport.
Don't forget, Acura TL, Infinity G37, Lexus IS, all have seat warmers too. All score higher than the LS, all in the same price bracket. The LS simply is rated terrible, not because its luxury (considering the MKZ is actually RELIABLE in consumers reports) but because Ford built a Bad Car.
The public mistreats all Cars, not just Fords. Consumers Reports is the PUBLIC complaining about issues. Not biased in any way. Weather you like it or not, Its officially accepted as an unreliable car.

Edit: And before anybody says "Consumer Reports is paid by Honda" or some stupid BS, actually go pick up a new issue or subscribe and See the FORD Modeo, FORD Fusion, and many other Fords make their TOP 10 cars.

 

[lincoln_zero]

- Front Driver bearing
- Front Passenger bearing
- Front Driver [upper] Ball Joint
- Tie rod end


Bad luck, random part quality problem, harsh pot hole impacts? Using bigger than 18" rims?
I've had one front wheel bearing failure (with lots of warning so that it was replaced before it was anything more than a noise problem). It happens...
Stock Rims. Paved Roads. Mixed hwy / city driving.

- 8 Coil packs

They are not coil packs. They are COPs. There is a difference. Unfortunately, COPs are a maintenance item on the LS. They shouldn't be, but we all know that they are. Get over it. I've replaced all the COPs and plugs on both of my LSes, one at about 70K, and the other at about 85K. I did this at the first sign of misfire so that I wouldn't have to replace my cats.
One of the many, many common issues making this car unreliable...

- Driver window motor
- Rear Driver window motor

Odd, but I did have one window motor fail on one of my Grand Marquis once. I've had to replace a window regulator on both LSes, but I'd had some of those fail on every car I'd had. (I tend to keep cars to a fairly high mileage.) Window regulators are wear items.
Canadian winters? Cold climate is just brutal on anything. Still had 2 fail regardless


- Alternator
- Clock Spring
These are wear items too. I've haven't had to replace either in either of my LSes, but I've certainly worn out alternators and clocksprings in some of my other cars.
Replaced mine on the 2002 around 160k Kilometers (158 miles?) Hasn't been an issue on my Friends Acura's And is it listed in the hand book as a maintenance schedule?

- Front Passenger caliper
- Rear passenger caliper


Really? Why not complain about replacing brake pads and rotors too. These are wear items and your mileage will vary. Same story as before. I haven't yet worn out a caliper on either LS, but I've had calipers to stick or leak on other cars and had to replace them.
Calipers were not warn, They leaked. Seal failures on both. Don't see how this is regular maintenance. A Third caliper is now leaking.

- Windshield (Twice, Cracked from pressure. Fail Ford.)


Not sure how that's Ford's fault. I've had both windshields replaced due to rocks hitting them. My insurance fully paid for it. Several years ago (on another car), I went through about four windshields in a year. Finally, I insisted on using a different company to replace the fourth one (the insurance did by then too). The guy that replaced the first one had left a piece of glass down in the calking and the other people missed it too. I guess that for Ford's fault?
Specified: The metal under the shield swelled from corrosion. Glass guys informed me this is NOT supposed to happen. Its sealed. The swelling applied pressure and snapped the shield. Glass guy sanded, and primed. Advised me it will happen again, nothing I can do. Also they informed me the previous Glass was replaced correctly. Just simply a Flaw in manufacturing.

- Serpentine belt
Really? That's scheduled maintenance. Check at 100K miles and replace by 150K miles. I've replaced mine when doing cooling system work, so they only made it half as long. However, the ones I replaced still looked really good and I think I could have reused them. Being interested in keeping things reliable, I didn't. It used to be that you were doing good to get 30K miles out of a belt.
That one you got me.

Glad you took the time to try and clear some of that up. Now heres the rest of the list:

- Driver seat warmer
- Passenger seat warmer (failing)
- Another Caliper (failed yesterday, leaking Break fluid)
- Defective ABS Module, Disables under Freezing temperature.
- Heating is defective. Needs 20 minutes to warm up to get SOME warm hair, partially defrosts due to this issue.
- Heated mirrors
- Rear view mirror compass
- Advance traction disables when -10 Celsius outside.
- Door seals are swollen/shrinking and no longer holding together.
- Constant vibration from rear tires. Feels like both bearings are warn
- in the 7 years, Always get steering vibrations on highways.

I dunno if doors seals are maintenance in the handbook? But the rest, doubt it. Do I have a lemon? I doubt it, because all that is failing, Just so happens to be whats listed as failure items in Consumers Reports

 

[lincoln_zero]

Also, I understand some of that is regular maintenance, but how is ANY of that MY fault directly, like you suggested? If driving a car is causing it to fail, then there s a reason Ford was almost in bankruptcy lineup with GMC. I dont have a link to the consumers reports.

All the problems I have, Many.. many many many many other Lincoln LS drivers have experienced.
Notice I have all Breaks, Suspension, and Electrical issues? Those are all Rated BLACK in consumer reports.

 

[1LoudLS]

if you have been driving around much with a miss fire going on, there there is damage to the cat, I doubt that the mechanic made that up if he did his testing properly.

 

[Jesus A Rodriguez]

Bad news I think I'm going to have to replace it because now I have white smoke coming from both exhaust pipes smfh.

 

[toby1234]

Did the car ever smell like a rotten egg after hard acceleration? If I get on it hard for about two gears straight, I'll get a rotten egg smell from the exhaust. I had that issue for the first thousand miles I owned it and now the check engine light came on with that p0420 code. I cleared it, and it stayed off for about 100 miles, then came back on. Car drives fine though. No misfires or hesitation.

 

[LS4me]

Here we go again......... My LSes have also been reliable with what I consider normal maintenance and one or two not-so-normal repairs. The current rear-end issue has me a bit put-out, though.

As for CR; their ONLY source of information is subscribers who own the specific reviewed product. Not very scientific, especially as they ask for opinions. Some think having to replace brake pads, fluids (other than oil) and such are unacceptable. I bought a TV on CR's recommendation years ago. It failed a week (power supply) after the warranty expired. After learning their non-scientific methods and the failure of the TV I swore them off. Like the BBB, they can be bought.