Clearing the check engine light

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TonyLS

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2004 V6 LS 122,000

Check engine light has been on for months, code indicates one of the cat converter is bad. My mechanic gave me a price of $1050. The car runs great and would like to try to get a sticker with the bad cat. A couple of questions:

- I gather that disconnecting the negative terminal to the battery for a while will reset the CEL, true?
- Do I need to do anything other than connecting the battery back up and starting the car? Will the computer fire up fine? I realize that I will lose the stored driving habits that the car has learned but that isn't a big problem. I also heard that resetting the CEL using a diag scan tool would also erase the stored driving habits that the car has learned...is this true?
- How long should I wait after clearing the check engine light before going for a sticker? I heard that if I go too soon the inspection computer knows that the light has been reset before the car has gone through it's full diag checks.

I'm having a hard time justifying this repair given the age and mileage on the car. Since I have had a few coils gone bad on both sides I'm concerned that if I replace one cat the other will have to be done soon after, then my luck the transmission, then.....

Any other suggestions would be appreciated.

I did see a nice 2010 mkz with 12,100 miles on sale at a dealer for $25K, good deal I think.
 
Part of car ownership is maintenence. Find a custom muffler shop and have them weld on some non oem cats. You can clear the light but it won't pass inspection right away and will come back on again.

That car can last another 100k miles easily. An mkz is nothing but a rebadged fusion.
 
I have the same issue on my 04 v6. CEL has been on for months. Had a couple bad coils a year ago and drove on them too long. Replaced all coils and plugs but the cat had already shown up as bad. Could also be the O2 sensors but I haven't paid to have them checked yet. Code read P0420 Bank 1 catalyst below efficiency. I have my fatherinlaw hook up his scan tool and cleared the light last weekend. Drove 500 miles since then and no light, no issues. We don't have inspections in AR but I guess that is what you mean by "going for a sticker". Can't help you there. But clearing the code with the scan tool does not reset the learned habits of the car.

If you are interested in getting it fixed RockAuto.com has the cats for something like $280 each, direct fit.

Skip the MKZ and the payments...
 
Any way that you clear the light (except for fixing the actual problem) will also clear all of the monitors. Since you really have a problem, the light will come back on by the time that the monitors complete. You will fail if you have a problem, or if the monitors aren't complete.*


*: Some states allow one monitor to be incomplete.
 
I had a 1996 Ford - first year of OBDII. That early computer wasn't smart like the newer computers. I would disconnect my neg batt terminal for about a minute, reconnect (check ENG light would be out) then I'd drive 27 miles on the highway - turn around, and drive 27 miles back to the Emissions Check point. Key off - hand the truck over and it would pass every time. The old OBDII's couldn't communicate the "limbo" status to the state test computer... the new stuff most certainly can. You can try it - but I have no confidence that it will work for your newer car.

1000 bucks is cheaper than a new car and more expensive insurance...
 
I had a bad rear O2 sensor on my LS - You can buy an XCAL and have the tuner "turn off" the rear O2 sensor in the tunes... I was already looking to buy one, so this was all the justification I needed :rolleyes:

The car just passed emissions again 2 weeks ago - so I've had zero issues the last 6 years with that fix. Just one option for you
 
I have this same situation now. But I realize (after reading this thread) I did a few things wrong.

1. I disconnected the positive terminal not the negative.

2. I didn't drive it long enough drive before I went to the smog shop.

I failed initially because there were no memory in the sensors.

The shop said drive it for 50 miles then come back for a retest. The check engine light came back on at 36 miles.

I've drove with this light on for years and have spent money in the past to correct this issue but, the light just returns. The car seems fine and runs great. Its an 2004 with 160K miles.

I really don't want to put any major money into it at this point and I'm not looking forward to a new car payment. I also love this car and not ready to give up on it, I guess I'm torn on what to do.

Sent from my DROID Turbo64 via Tapatalk
 
luvmylsv6 said:
I really don't want to put any major money into it at this point and I'm not looking forward to a new car payment. I also love this car and not ready to give up on it, I guess I'm torn on what to do.
Click to expand...

You've answered your own question. Whatever repair you need (have you at least read the code?) is far cheaper than a car payment.
 
You could buy an inexpensive code reader and clear the code a few blocks before going to the inspection. Or of course, you could fix the problem.
 
All2kool said:
You could buy an inexpensive code reader and clear the code a few blocks before going to the inspection. Or of course, you could fix the problem.
Click to expand...
Will the code reader erase the memory as well?

The computer flagged me for not having any memory from the sensors because I disconnected the battery.

I understand that the code reader will clear the engine light but, will it erase the memory as well?

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luvmylsv6 said:
Will the code reader erase the memory as well?

The computer flagged me for not having any memory from the sensors because I disconnected the battery.

I understand that the code reader will clear the engine light but, will it erase the memory as well?

Sent from my DROID Turbo64 via Tapatalk
Click to expand...

Won't work... The smog check machine will check to make sure ll systems are ready and store no codes. There has to be "drive cycle" (OH NO!!!!!! I said Bettlejuice!!!) completed for the the sensors to be "ready". The machine will show the sensors as "not ready" if the cycle hasn't been completed. That's why the guy said to drive 50 miles. I've simplified the actual procedure quite a bit.

There is no way you will get a successful smog check as long as the light keeps returning. You will need to bite the bullet and get whatever system is "broken" fixed.
 
All2kool said:
You could buy an inexpensive code reader and clear the code a few blocks before going to the inspection. Or of course, you could fix the problem.
Click to expand...

once he clears the codes, then he fails...


that's the whole point, they want to see the car driven long enough that the computer completes all of its requirements and then shows no codes...

luvmylsv6 said:
Will the code reader erase the memory as well?
Click to expand...

yes


you need to fix the problem so that the code doesn't come back, then you can pass the test.
 
Is it possible to go to another smog shop and hope for better luck??? Or does the system track that as well?

Sent from my DROID Turbo64 via Tapatalk
 
so then you are hoping to find a shop where the guy running the test is not doing the job he is paid to do? good luck


well, people are human after all, I'm sure if you wave enough money in front of someone, sooner or later you'll find somebody willing to look the other way. however waving money in front of a repair man could also just as simply get the car fixed with out having to bribe people running compliance for the state.
 
luvmylsv6 said:
Is it possible to go to another smog shop and hope for better luck??? Or does the system track that as well?

Sent from my DROID Turbo64 via Tapatalk
Click to expand...

No. New procedure is to plug the machine into the OBD port. The machine checks all the emissions sensors for proper readings. The "sniff" test isn't used much. I was surprised when I did the smog check to sell the 2000 LS that that's all they did. The guy told me that that's what they do now.

And.... The results are automatically and instantly sent to SacraDEmento.
 
All2kool said:
You could buy an inexpensive code reader and clear the code a few blocks before going to the inspection. Or of course, you could fix the problem.
Click to expand...


:: voted "worst ever" advice 2016

poor.jpg

poor.jpg
 
2 cents. In cali, there is a part of the law that says if you spend x amount of dollars at a qualified shop trying to fix the issue, then you get an exemption if you still fail. I dont know exactly what amount or how it works, since I always pass. Seems to me you should find a shop that will take care of the cat at the most reasonable price. The alternative is start with the car payments again.
 
I guess I am wrong - which never bothers me because it means I learned something. I had no idea that clearing a code also cleared the 'drive history'. Good to know this.
 
Clearing the codes, also clears the monitor flags. This is a legal requirement. The monitor flags must not set until enough time/miles/conditions have passed for the PCM to be sure that it would have detected (and indicated) any emissions problems present.
 
LS4me said:
No. New procedure is to plug the machine into the OBD port. The machine checks all the emissions sensors for proper readings. The "sniff" test isn't used much. I was surprised when I did the smog check to sell the 2000 LS that that's all they did. The guy told me that that's what they do now.

And.... The results are automatically and instantly sent to SacraDEmento.
Click to expand...

NJ just sent out notices that pre-1996/pre-OBDII cars no longer have to be inspected, presumably so that an OBDII scan and a brake check are all that's needed. No sniffer, no light check, certainly no actual visual inspection on a lift (drive-through style inspection).

Several states are moving to instantly uploading results (read: failures) to the DMV headquarters.
 
man for all the sh!tty weather I have to deal with, I guess there is a silver lining to living in a non inspection state!
 
FDR said:
NJ just sent out notices that pre-1996/pre-OBDII cars no longer have to be inspected, presumably so that an OBDII scan and a brake check are all that's needed. No sniffer, no light check, certainly no actual visual inspection on a lift (drive-through style inspection).
Click to expand...

Texas has a rolling 20 or 25 year exemption. "Old" cars only need a basic safety test (belts, lights, horn). This was mainly to get rid of the sniffer/rolling road tests as quickly as possible, so they may change their mind for OBD-II and later cars.
 
KS is only when the vehicle is registered in the state... So only needed once... EVER :wrench
 
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