A hair-raising ride to reset the smog monitors

I've been meaning to report this for awhile. The car's a 2000 Sonata.

As of a year or two ago, to the best of my knowledge, Hyundai kept the
drive cycles a secret, even from their own service shops. Hyundaitech
confirmed this. I'll describe "drive cycles" below.

In order to pass a California smog test (every two years), all of the
car's testing programs have to have been run and completed. And they
have to have reported the functioning of all emission sensors and their
data in a "pass" status. These programs are called "monitors." The State
allows two of these monitors to be incomplete. The status is shown on a
hand-held code reader. If the cycles aren't completed, the smog shop
cannot certify the car.

I had a broken emissions hose; the dash light was on for awhile. Nothing
critical, but still, not legal. We fixed the problem, but still had to
ensure that the repair "took," and cured the status in the computer. To
begin with, I wiped the computer's logs so we could begin to rebuild
the data (done with the "clear check engine light" button on the code
reader.

In order to run these tests, the car has to be put through one or more
"drive cycles."

I spent a lot of time digging around, and finally found the drive cycles
in a Motor's publication: a large book at a nearby smog test shop. The
manager was kind enough to copy the two pages for me.

For most cars, short drive cycles are published individually for this or
that emissions system. Hyundai doesn't publish any for my car. What's
almost worse is that instead of using those short cycles, Hyundai uses
two humongous all-purpose sequences. One is supposed to emulate city
driving, the other highway driving. Each of these tests takes about 1/2
hour. They are neither easy or safe.

I had a savvy friend ride shotgun. I drove, and he watched the road,
read the instructions to me, and timed the intervals with a stopwatch.
The whole procedure is nerve-wracking. It includes speeding up,
accelerating and decelerating according to a strict schedule, and
maintaining unsafe speeds on both city streets and highways. For
example, the company seems fond of 40 MPH: that's over the speed limit
on the streets, and slow enough to get you rammed on the highway. It was
a teeth-clenching trip.

The good news is that it worked! The monitors were reset (except for the
allowed two), and the car passed the smog test. I don't recommend that
people do this if they don't have the unusual road conditions required
to do it safel. It may be much better to pay the smog shop to run the
test on the dynamometer instead. I ran the cycles in daylight, on a
Sunday afternoon, on suburban streets and the most deserted highway I
know of -- still a hair-raising challenge.

Richard

 

Yes, I just went through this with my 2002 Sonata 2.7. After
changing the gas cap, I had to drive the car around for about 120
mi; then the CEL came back on. Rinse, lather, repeat.

Since the error was for the evap system, I had to wait for it to
run the test, or take it to the dealer for $90.00 "die agnostic" fee.

I wish they would just program the ECM to run the tests after
the CEL was reset, or make available the info on how to make it
happen.

 

For that money, you could buy a little code reader and save the BS
(maybe). As I understand it, your car's computer really runs the tests
itself in due time, so all the dealer's doing in this is what the little
code reader does. Granted, a professional "scan tool" can dig much
deeper into symptoms and/or what the sensors have reported. This helps
in performing repair work. Running the drive cycles should hasten the work.

That's exactly what does happen. But it takes that 120 miles, or even
more. Different of these cycles have different criteria and take
differing amounts of time. Some sensors are "satisfactory" fairly
quickly. Others may require 40 starts in order to make the computer
happy. These systems are "intelligent," and I was impressed with the
sensibility designed into them.

Well, the "they" in this case was the Motor's smog test manual, used in
the smog shops. My theory about Hyundai is a hunch. I believe that the
company bought key technology for certain systems from other auto
makers, and that they had to catch up slowly. So, the drive cycle
business was much more primitive in its implementation. They came up
with this "one size fits all" method. It works, but I think that it's
scary and potentially dangerous, especially if one doesn't think it out
very well beforehand. It's no problem running these two mega-tests on
your test track -- you just need your own test track. Otherwise, a
well-meaning friend is a godsend. In my case, my friend had bought a
code reader just like mine, and he was interested in learning more about
the ins and outs of these systems.

This was a couple of years ago. The manual that came with my code reader
is excellent. It explains a lot about how the diagnostic criteria are
implemented and gives excellent historic background as well. The brand
is "Equus," but I've forgotten the company's name. They're based in
Taiwan, but engineering's done here in California. In usability, it ran
circles around the competition for me (I tried the two other brands).

I believe that, let's say, if you disconnect the car's battery, you can
keep the computer's memorized data alive by connecting another battery
to the system. In fact, a bunch of flashlight batteries in a holder
should serve the purpose.

Hyundaitech, please correct what I've written if you feel that I've said
anything that's off-base.

Richard

 

I don't know if the driving series was posted, but what is the danger and
what makes it scary? Do you have to drive in excess of 70 mph? Go through
stop signs?

 

I do, in fact, have a code reader. It's an Actron and cost about
$90.00. It does not have the ability to force the evap test. The
NYS Inspection station has a more advanced scan tool, and I
(against my better judgement) paid them $65 for their
"diagnostic" which reported the same code the Actron reported.
They said they were not able to force the evap test, nor were
they able to tell me what kind of driving would cause the test to
run. Hyundaitech has stated that the dealer's scan tool can force
the test.

<snip>
Well, I understand that some of the tests need the car to be
driven, perhaps under various conditions, to complete. However,
it doesn't seem that having a small evap leak would require much
in the way of prerequisites ( I think I read that the tank needs
to be less than 80% full).

What did you gain by having a friend monitor the scanner while
you drove? Does yours display data in real time? I don't know
that mine does, I will refer to the manual. Since I don't have
anybody do watch the data for me, trying to run the scanner while
driving the car could end my problems with that particular
car..maybe *all* my problems <g>.

Thank you for your response.

 

I didn't post it: it's a picture, not text.
What makes it scary is that you have to maintain fixed speeds for
specific durations. This may indeed put you through stop signs and red
lights.

And as I said earlier, you have to maintain 40 mph a lot, which is over
the speed limit on city streets around here, and slow enough to be
rear-ended on the freeway. So, visualize someone coming up on your tail
on a two-lane highway doing 65 while you're doing a steady 40. I had my
blinkers on.

Richard

 

I don't know your particular code reader, so I can't comment on it. The
one I use checks the sensors quite frequently if it's plugged in during
the test. But that wasn't what I was looking for, so we didn't have it
working. Please search on "drive cycles" to see if you can get a handle
on the subject. It's not simple.

Note that the sensors (and their individual codes) aren't the same thing
as drive cycles. But the drive cycles (computer programs) do monitor the
sensors under dynamic conditions.

So, my friend did not monitor the scanner. He read the driving
instructions to me one step at a time, checking the timing for each one,
warning me when to expect the next step, reading it to me in advance. I
watched for rear-enders on the highway, as did he, space around the car
while driving, etc. We watched for police as well. I picked a city route
to avoid stop signs and lights, but since we needed smooth, flat
straightaways, this wasn't always possible.

There's just too much to pay attention to at the same time. If you try
to do all this by yourself, you'll wrap your car around a tree.

The task was to run each sequence continuously according to the script
with no deviations. The goal was to ensure that one code, in particular,
had been recognized as reset (one of the O2 sensors), and that its
related drive cycle was complete. To both of our amazement, the whole
insanity actually worked. So, it was only after the end that I connected
the reader and all was well. And then onward to the smog test.

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

Now, the gas tank business is something special. The reason why I say
this is that I've seen the smog station put a special box onto the gas
filler in order to test the plumbing on the tank. The hand-held tools
don't do that. The code reader reveals two things:

1. Codes stored in the computer, even if the check engine light hasn't
been turned on.

2. Which drive cycles have been run to satisfaction.

Nothing more.

I don't know more than this. Driving the car for long enough may or may
not run all the monitors to conclusion soon enough to make our smog test
deadlines. So running the cycles speeds things up. Yeah: it's a pain,
all right.

Richard

 

I don't understand - why not head out to where rural roads allow for that
kind of driving with no problems? I can think of plenty of places to go
that would allow for that kind of driving without referring to it as a hair
raising experience.

 

I guess I don't see it as a problem. Every day going to work I drive a
stretch of road with a 40 mph speed limit for 5 miles, then it jumps to 45
for another 9 miles. There are a many rural roads that are similar so I can
do that in most every direction from where I live in CT in The Last Green
Valley. If you live in Brooklyn NY though, you may never hit 40 in days
of driving.

 

After accounting for the miles added to your odometer (I think the IRS
allows $0.485 or something close to that per mile), just how much did
you save compared to paying a dealer to use their scan tool?

Matt

 

Voyager wrote:

Please note I am not the original poster. Well, the first 120
miles were trips I was going to take anyhow, and done while the
NYS 10 day sticker was valid.

The next two trips were done after the sticker had expired,
putting me a risk for a ticket. They also were not "required"
trips, so they were wasted gas.

I also paid for a NAPA gas cap, then a $65 "diagnostic" at the
garage that did the inspection, then two Hyundai gas caps after
the garage said the NAPA gas cap might not fix the evap code.

All in all, it wasn't the greatest experience.

The dealer wanted $90 to run a diagnostic. When I asked how they
would track down the code P0442, they got vague and hand-wavy and
told me the car has 105 sensors and it's difficult to say how
much work it would take.

I wanted to avoid the horror stories I see often in auto forums:
"I take my car in, pay $300, and the CEL comes back on a week later."

Best case: I take the car to the dealer, he tracks down the
problem (a broken vacuum hose), fixes it, verifies the fix by
forcing the evap test, and charges me $90 plus, say, $50 to
replace the hose.

Worst case: I take the car to the dealer, pay $90 one or more
times, buy gas caps and purge valves and vacuum hoses and it
winds up costing a real lot of money and time and taxi fees since
the dealer is not within walking distance.

If I had to do it again, maybe I would just take it to the
dealer. With 20/20 hindsight, I would have just examined the evap
system with a bright light, found the broken hose, and skipped
the whole gas cap/garage diagnostic thing <g>. Hyundaitech did
tell me to examine the system for broken hoses etc. Regrettably,
I did not take his advice to heart because I was unfamiliar with
the car and have been very pressed for time this fall. I think it
also helped that the sun was low enough that it shone *right on*
the cracked vacuum hose the day I found it.

In strictly financial terms, I'm not sure I came out ahead.
OTOH, I learned a lot about scan tool use, evap systems, my
Hyundai, and other fun stuff which may save me money or trouble
in the future.

 

Don't you think that maybe when they say 40 mph, that they might mean - at
least - 40 mph so it gets the auto transmission up into the highest gear
and locks the torque converter? The other requirements are probably along
the lines of things that would equate to a "steady state" condition to let
the ECM figure out if what it calculates it's doing is really what seems to
be coming back from the sensors. For example. they might have buried it in
the firmware somewhere that in 4th or 5th gear (whatever the high end is for
that car) in steady state with loop closed, with x MAF input and y TPS with
injector pulsewidth of z should equal somewhere around $7F from the DAC on
average. I don't think that it is possible that you could drive at exactly
40.000 mph. The other pieces of the recipe that you have probably induce
variables that it should be able to solve for assuming that no one has
replaced a possibly defective sensor with a pot, or tried offsetting some
sensor input in a effort to get around the differences between the upstream
and downstream O2 sensors that would be expected but not present if the Cat
was a piece of pipe.

You probably hit most of the requirements fairly quickly through normal
driving. Now that you've been inspected, why not reset it again, and see how
long it takes to clear with "normal" driving.

 

You're probably correct, but Hyundai, remember, has kept this a secret
from their own dealers. The routine worked for me, and of course, one
cannot achieve precise tolerances with the gas pedal. The recipe calls
for other maintained speeds, acceleration/deceleration routines, and
more. There's nothing in the instructions to indicate more or less, "at
least," etc.

Again, obviously, the needs aren't totally precise -- but we don't know
anything more than that the routine definitely worked for me.

No: I did not. If this had worked, I would not have gone through the
trouble of doing this insane procedure.
And I'm not going to go through this again unless absolutely required.
You see, I have to do another smog test within the next two months, and
I just don't need more aggravation.

Please understand that I didn't just decide to do this: I did quite a
bit of research, including interviewing an engineer at the State Air
Resources Board for a half-hour. On the subject of code readers, based
on an earlier series of posts right here, I was interviewed and quoted
on the subject by _US News and World Report._

I know that I started this thread. I wrote the piece as a contribution
to the NG. However, I just can't spend any more time with this
discussion about why I didn't do this or that. Pardon me, please, but
I'm now worn out about this. The rest of you, of course, are welcome to
continue the discussion.

I actually came back to get some advice about my window problem, so if
any of you have had a driver's door of a 2000 Sonata apart, I'd welcome
your replies to my previous thread.

Enjoy

Richard

 

Thanks for reporting, Richard.

It's my opinion that the drive cycle you have is simply one way of gettin
all the tests to run. Some tests must run and pass before others can ru
and pass. Some need certain coolant temperatures, calculated engine loa
values, rpm levels, or vehicle speeds. You probably don't need to d
things exactly the way the drive cycle says, but the problem is tha
Hyundai doesn't actually tell us what specific things are necessary fo
each test.

For example, for checking the catalyst efficiency, it's necessary for th
oxygen sensors to have been tested and passed. On the other hand, on th
evap test, I don't think anything needs to happen except that you need t
reach whatever criteria the ECM logic has set for running the test.

Older Bosch-controlled Hyundais ran the evap test at the first stoppe
idle after the vehicle had been running twenty minutes. If the vehicl
wasn't stopped long enough, it'd try again at the next stop.

And I think you're at least half correct on the fuel management system
Hyundai uses. Most are reverse engineered, meaning that Hyundai takes
fuel management system already being used and tweaks (or has it tweaked
to operate their product. I don't think they're as primitive as yo
imply, but rather that the Koreans are very secretive and closely guar
proprietary information. It's much better now, but there have been time
I've fought a check engine light-related trouble code without knowin
exactly what the ECM must see in order for the code to set.

 

This makes sense to me, from what I know about Korean companies in the
Electronics field. And I'd expect improvement also as time has gone by.
As I recall, Hyundai is a family-owned conglomerate: as such, I'd expect
them to hold control tightly. This isn't necessarily a bad thing, since,
at least in hi-fi, it's only after the company goes public or ownership
changes, that quality begins to slide, often dramatically. Hyundai has
been trying to overcome a bad reputation; that's a wonderful time to
buy! (It used to be for Chrysler products.)

I expect the Koreans to catch up in the technology department. In
electronics, 20 years ago, their "packaging engineering" produced a far
more repairable product than what the Japanese were turning out. The
Japanese were getting into un-fixable products because they'd figured
how to manufacture in layers, stuffing things into impossible clearances
with everything obstructed. I got to hate the most popular brands. I
think that the packaging engineering of the Korean products was actually
done here (our engineers tended to be pretty considerate).

Korean high-tech products have been designed right here. For example,
Samsung and other companies have done lots of their R&D work in Silicon
Valley.

See ya.

Richard