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Hello all,

The maintenance light (not engine light) has been on for awhile (several months). According to manual, it it usually time for oil change and etc. Last month, my car had smog check and PASSED. Yesterday, I took my car for timing belt change at honda dealer, the advisor at honda told me that i have a bad catalylic converter. My question is what light will be on if catalytic converter has problem? Thanks

 
Rep Power: 188

well the check engine light would. but he is probably just trying to get you to buy a new one if your over 100k miles because thats "the normal lifetime of a catalytic converter" but they almost always last way longer depending on what octane you run and such.
but you should have a check engine light throwing a code for the secondary o2 sensor if your converter is bad, if not your fine especially if your passing smog.

 
Rep Power: 188

I would ask why they think it is bad. As mentioned above the check engine light would come on. Here is some more info for ya..just nice to know

The EPA's rules for replacement are quite strict: a repair facility cannot replace a converter until it is out of warranty and a legitimate need for replacement has been established and documented (such as a blockage, failure of an emissions test, or to replace a converter that someone removed). The repair facility must also obtain your authorization for repairs in writing, keep the paperwork for six months and the old converter for 15 days. The replacement converter must be the same type as the original and installed in the same location. These rules do NOT apply to the vehicle owner, so you may replace the converter yourself if the converter is defective.
The federal emission warranty on OEM converters is 8 years or 80,000 miles. If your OEM converter is still under warranty, you should be able to get a free replacement from your new car dealer. If it is out of warranty, you can take it to any repair facility or change it yourself.
Replacement converters must be the same type as the original, and OBD II vehicles require an OBDII certified converter. The new converter must also be installed in the same location as the original.

 
Rep Power: 285

Just so you know, it takes about ten seconds to turn off the maintenance light and it's strictly odometer based, which means it doesn't actually tell you anything.

A CEL will not necessarily turn on when a cat or o2 sensor goes bad as well, the code can be stored in the ecu with no indication until someone checks for it.

 
Rep Power: 518

Thanks for that. Let me add:

Those codes turn on the CEL. The CEL might turn itself off if the self test ran and passed X number of self test times, but the CEL came on at the onset when the code was set. Code is retained in memory for quite a while before it is cleared on its own, if there were no more failures.
Seems like every code has its own set of criteria for PCM monitor testing and turning on or off the light.
Do you know of a specific code example related to O2 or cat that does not turn on the CEL?

Although I will say that there are ways an O2 sensor can fail and the PCM doesn't see it as bad. Therefore no codes. I see it on older cars, the PCMs weren't as smart or programmed to be as sensitive as newer stuff is.
The newer the car, the more sensitive the PCM is.


Wrong, just plain wrong. *shakes head*
If the secondary O2 sensor is bad, there are several different codes that address different failures.

An O2 sensor code is NOT a cat code. It is an O2 sensor code. That's it.

A bad cat will throw a code of its own....
If the monitor ran and failed. O2 sensor codes and some other codes can prevent the PCM from testing the cat. So a bad O2 sensor code can literally HIDE a cat code by preventing self tests.

HTH

 
Rep Power: 285

I've never been fully informed why certain times a code activates a CEL while other times it doesn't, but if there's code specific programming that makes sense.

I do not have an emissions specific related example for a Honda, but I have seen a faulty 02 sensor not activate an indicator light on a jeep. I wasn't sure if that can also happen on a Honda, my knowledge of the finer details of PCM monitoring is a bit weak.

 
Rep Power: 518

I'm on a roll now!

Like a P0463 in most GMs won't turn on a light. Fuel level sender. It could halt the evap tests, or make the test results inaccurate.
No idea why the GM engineers thought it wasn't important enough to turn on the light.
Probably interpretation of the EPA rules.
If the EPA didn't mandate that the light must come on for such and such, the engineers didn't turn it on. They do NOT want the light to come on. 75% of GM cars for more than a decade of model years would have the light on for that code. And other makes that used those same Delco/Delphi parts.

ELD code in Hondas doesn't turn on the light. Maybe they do now on newer cars, I haven't seen problems with them yet. And I am not going go digging into that info now. But ELD is not an emissions related code.
I bet there are a couple of other codes that don't turn on the light, but I can't think of them right now.

Maybe I should have said "those particular codes" re: O2's and cats.

And there have always been faults that the engineers couldn't have ever predicted would ever happen, so for those faults the computer can't set a code.
Or the code might be totally unrelated to the sensor at fault.
Or it can't see the fault.
Plug in a sensor that is completely wrong in construction or materials, then breaks, but still has a signal value that the computer accepts as possible........
(A Zirconia O2 sensor that breaks causes voltage inversion. In a wrong application where the computer wasn't programmed for that sort of failure, it goes stupid. The A/D converter can't differentiate between pos and neg voltage, all it sees is a voltage and adjusts fuel accordingly. Garbage in, garbage out. No light. Exhaust emissions go through the roof, but the computer can't see it.)
Lots of possibilities.
Seen one or two.
Not bald yet.

Back in the olden days of EFI, like in the 80s for Asian cars, ECMs weren't nearly as sophisticated as they are today. Open or short circuits may have been the only criteria they were programmed for or maybe that was all they were even able to judge. And no memory. You had to check the (flash) codes WHILE the problem was happening. If the short went away, the code disappeared. Damn hard to find any intermittent faults. No warning light that the driver could see. The car nearly had to die before the driver knew there was any issues.
Forget real codes with numbers on a display. Forget flash codes from a light on the dash or an LED in the ECM.
Try getting fault codes using a dwellmeter.

Diagnosis is great today, if one understands it. There is a LOT to comprehend now, on top of engine basics.
If it isn't understood, one may just read a code and throw a part at it. That only works sometimes.

 
Rep Power: 188

Good info Ezone..i must say I have an appreciation for your level of knowledge.

 
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where exactly is this ECU located? i know its the brain and I understand that by disconnecting + reconnecting the battery, I reset the ECU.
Is this kinda part of every Honda, or a specific location where this ECU is found?

 
Rep Power: 518

Different places for different years.


What car?
What are you calling an ECU?
Why do you think you need to know this information?

99.9% of drivers have absolutely no business touching the computers, or even knowing where they are at. Rarely will any good come from it.

As a professional electrical and driveability tech, even I don't hardly ever need to touch the computers. Seriously, I have really had problems with about fewer than 10 of them in my almost 9 years at this dealer.



Here's some low hanging fruit:





Don't hurt yourself. HTH

 
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I have a 2003 civic ex 4dr sedan 1.7L engine 4 cylinders.

What are you calling an ECU?
Why do you think you need to know this information?

Im of the belief that i m having transmission, overheating and idle problems becoz of the ECU.
I want a solution to it, and want to know if that is something i can do it myself or a Honda Certified mechanic/technician is better able to do it. (I am not mechanically inclined or show any symptoms/tendencies of having to un-screw &/or re-screw, get under the hood of the car and do mechanical /repair work on my own ; so having said that, i would always lean towards a ASE/Master Mechanic for my work? AND THAT COSTS $$$$$$$.

I also understand a lot of Re-Learn procedures and my understanding is it comes from the ECU for various parts/divisions of the Honda Civic Car.
The way i c it is if the brain (THE ECU) gets all the right signals then there never is a need to have CEL.
I have had MAP sensors,(P1129) replaced, IAC valve cleaned and Replaced (P0505) and the way i see it is if after removing/replacing the MAP sensor and installing it properly and having taken off the wires from the battery to let it remove the MAP sensor code from the CEL and having driven for nearly 200+ miles before going back to Autozone and having a CEL read again only to find out that the MAP Sensor code (P1129) it has never really disappeared from the CEL list of codes but you did replace it and did the re-learn. and having paid Zillion $$$$$ to a certified Mechanic for the work, where did i go wrong? what gives?
If in my opinoin the brain of Honda (The ECU) is getting this as a wrong signal what am i MISUNDERSTANDING here? i just dont know?
All i can and know and tell is that i had IAC valve and MAP sensors replaced and both after having re-learned have re-appeared on CEL. I find myself so very disappointed of seeing them on CEL that i would like to know and understand how exactly is it that the brain of Honda( the ECU ) is getting the wrong signals?

Most posts here would tell you to follow in sequence what exactly the CEL says and take care of it one by one instead of throwing money at what is not being shown on CEL?

I am so confused? i speak from my heart and tell it like it is? i m very very disappointed when i have to find out that after Spending XXXX $$$$$$ on the repairs/mechanics and taking care of the codes you still are BACK TO SQUARE ONE ,,,how do you understand/justify the expense of it all?

Now what has it got to do with the ECU???? (The Brain).
i would rather know if it gets the right signal then i have solved a problem versus knowing where the u know what is located?
I wouldnt personally ever wanna MESS with an ECU.

SAYING IT LIKE I C IT.. I MAY HAVE MISUNDERSTOOD...BUT THEN????????

 
Rep Power: 518

I have a 2003 civic ex 4dr sedan 1.7L engine 4 cylinders.

Im of the belief that i m having transmission, overheating and idle problems becoz of the ECU.

The 3 complaints could be completely separate problems. Or they could be related.
The cars have plenty of transmission problems.
The cars blow head gaskets. That could give you overheating AND idle problems.






I want a solution to it, and want to know if that is something i can do it myself or a Honda Certified mechanic/technician is better able to do it.

Someone COMPETENT that is familiar with the cars would be my first choice.
Finding that person is up to you. (Not many out there are like me, and I'm still only human.)

Dealers employ plenty of idiots too. They generate significant revenue for little cost.
Few shops anywhere are willing to employ a full staff of top shelf techs.


(I am not mechanically inclined or show any symptoms/tendencies of having to un-screw &/or re-screw, get under the hood of the car and do mechanical /repair work on my own ; so having said that,


That means you are not qualified to state that you need a PCM either.You are grasping at straws, and you picked an expensive one.



i would always lean towards a ASE/Master Mechanic for my work?

ASE is a start......

but

Here's a clue: ASE will pass a score of less than 60% correct.
(In high school, that would have been a failing grade.)
I know ASE Certified Master Techs that I wouldn't let fix a sandwich.




AND THAT COSTS $$$$$$$.

If you think a professional is expensive, just hire an amateur.

How much money have you already spent without a solution to the actual problem?

The cheapest people tend to spend the most money.



I also understand a lot of Re-Learn procedures and my understanding is it comes from the ECU for various parts/divisions of the Honda Civic Car.

I think I replied to your idle relearn question earlier? If it wasn't you, then search for it. There are only a few times that a relearn is truly needed.



The way i c it is if the brain (THE ECU) gets all the right signals then there never is a need to have CEL.

Probably true.
But your PCM sees something it does not like. You (or your mechanics) have not figured out why.


I have had MAP sensors,(P1129) replaced, IAC valve cleaned and Replaced (P0505) and the way i see it is if after removing/replacing the MAP sensor and installing it properly and having taken off the wires from the battery to let it remove the MAP sensor code from the CEL and having driven for nearly 200+ miles before going back to Autozone and having a CEL read again only to find out that the MAP Sensor code (P1129) it has never really disappeared from the CEL list of codes but you did replace it and did the re-learn. and having paid Zillion $$$$$ to a certified Mechanic for the work, where did i go wrong? what gives?


You are flying blind.
You (and AutoZone) don't have the equipment it takes to evaluate the problem.

I KNOW you don't have the info I would want to see if I was the one looking at the car.

What was the freeze-frame data stored when the MAP code set?
What data did the computer show at the very moment that the MAP code set?
What REALLY happened at the MAP sensor at that same moment?

Sure, it could be a bad PCM. Only a few people have reported problems. But for a cost of about $800 or so to replace it and program it, don't you think you would want to be more positive than to just hazard a guess?







--

If in my opinoin the brain of Honda (The ECU) is getting this as a wrong signal what am i MISUNDERSTANDING here? i just dont know?
All i can and know and tell is that i had IAC valve and MAP sensors replaced and both after having re-learned have re-appeared on CEL. I find myself so very disappointed of seeing them on CEL that i would like to know and understand how exactly is it that the brain of Honda( the ECU ) is getting the wrong signals?

Most posts here would tell you to follow in sequence what exactly the CEL says and take care of it one by one instead of throwing money at what is not being shown on CEL?

I am so confused? i speak from my heart and tell it like it is? i m very very disappointed when i have to find out that after Spending XXXX $$$$$$ on the repairs/mechanics and taking care of the codes you still are BACK TO SQUARE ONE ,,,how do you understand/justify the expense of it all?

Now what has it got to do with the ECU???? (The Brain).
i would rather know if it gets the right signal then i have solved a problem versus knowing where the u know what is located?
I wouldnt personally ever wanna MESS with an ECU.

SAYING IT LIKE I C IT.. I MAY HAVE MISUNDERSTOOD...BUT THEN????????
--





You might be the victim of an undertrained or undertooled mechanic.
You might be the victim of ignorance.
You might be the victim of someone unwilling or unable to take the time needed to evaluate and solve the problem.
I can keep guessing all evening.

Being smart in this industry does not pay well at most shops.
Chances are good that the stupid guy doing brake jobs all day is making more money than the guy that is smart enough to be diagnosing real problems.
Guess what happens.






A quote from another forum:
"Sufficient cluelessness is indistinguishable from malice." The consumer really has no good way of knowing if any one person or shop is honest and competent. One bad apple....... Most consumers have been burned at least once and are gun-shy now. They can't trust anyone now. Skeptical, leery. But they don't see many other options, and many keep returning to the incompetent again and again, with no satisfaction or resolution to their problems.

 
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Mechanics are like a BOX OF CHOCOLATES, u never know what you gonna get???//lol

ASE or NON-ASE certified.

 
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Its like try and try and you will succeed. Keep throwing parts at the car sufficient enough that the repairs exceed the KBB value of the car...lol

 
Rep Power: 518

Replacing parts is easy.
Knowing which one part to replace is not always so easy.
So they replace them all.



This IS a business model.

Keep throwing money at the car until the problem goes away, or the customer goes away.
The mechanic thinks he finally fixed it because the car didn't come back. No clue otherwise.

A slick talking salesman WILL convince the unknowing that their car really needed all that ****. The mentality of the general public buys into it.

Remove original parts that worked perfectly fine, replace them with low quality offshore parts that came in a plain white box. Charge out the wazooo for it.
And the car is still broken.


"FIXING cars right the first time" doesn't generate a lot of revenue in a shop.
The guy that fires the parts cannon is the one that looks good to the bean counters.

Handy pic of a parts cannon:



He generates tons of profit.
Short sighted management loves this.
Bean counters usually can't understand the long-term and repeat business.
Most management doesn't know jack sch!tt about fixing cars, so they have no clue when their mechanics have no clue. Mechanics with low ethics take advantage of this.


Many shops have at least ONE smart person that can bail out whatever the flunkies screwed up. Many don't.



By the time the car finds its way to me, the owner is usually out of money.

------------------------------------------------------

This applies to almost every profession, from fast food to the medical field.



Here is a copy of a post from a professional forum I frequent, posted by a Mr. Showers:

>What other industry is most like auto repair?

Construction and Home Repair.

Low barriers to entry, little or no entry level training
required. Anyone can do it.

Standards are usually a minimum, laxly or UNinspected at a
local level. No rules to speak of, except basic building
codes which are often easily ignored or bypassed.

A wide gap between minimum repairs and maximum repairs, all
resulting in similar apperance or outcome. And the
difference is easy to hide behind flashy signs and fast
talk.

A huge disparity in the quality of materials (parts).

Seasonal variations that make life more difficult.

Certification largely unknown and mostly irrelevant except
to industry insiders.

Prices seem to revolve around an industry norm with little
regard to costs of doing business.

THOUSANDS to choose from, and they come and go.

The best are booked out long in advance.

The good work is often visually indistinguishable from the
bad.




Certs are a start, but really not worth much.
Reputation and word of mouth are good.

 
Rep Power: 0

A little KNOWLEDGE is a dangerous thing? thats what i feel about whenever a car repair or home repair comes up? hate it both. I know & feel i do not have competency nor the full knowledge of repairing anything. so i m very dependent on trusting a mechanic for doing the work. I exclusively bet on mechanics from word of mouth &/or Craigslist posters and thoroughly interview them to know and understand if he is able to solve my problem. I anticipate consequences of my decisions, but someone's gotta do it.
Also, there is no such thing as a PERFECT HONDA MECHANIC...either.
so eventually whether or not you like it, you gonna have to trust someone to do it right, the first time, it does not necessarily solve the problem but then, if you cant ask questions and infer based on what he is telling you and make a wild guess on his knowledge of your problem, then you are making a bet that he is ready willing and able to solve your issue and that you will never have this issue he tackled appear back again and thats what i know best to do...otherewise, well, the car owner loses.

 
Rep Power: 518

Another issue I see from you is you are a "floater".
You float from shop to shop, never a repeat customer.
Nobody can know the history of the car, we would open the hood and see a bunch of new looking cheapo parts and assume you are not the type of customer we want.

CL mechanics for high tech stuff? Really? I bet you got what you paid for.



I'm human, like most of the rest of the people.
Some days I'm more human than others.

You have no idea what my ranking is, nor what my qualifications are, nor what is on my resume.


If you saw me in person, you probably wouldn't want me near your car....or your wife and kids.

 
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