More 99 Sonata trouble codes

Driving home from the shop after getting the crank sensor replaced in the 99
sonata 2.4L (I chickened out of doing it myself) the check engine lite came
on. Boy was I ticked off after paying out more than $400. I had the belts
replaced also even tho they were less than half way thru their life estimate
since I was paying out the labor charge to get to them. Anyway, when I got
home I read the codes, it was P0115 {engine coolant temp circuit
malfunction). I was somewhat relieved to see that it had nothing to do with
the crank sensor. My first thought was that the tech had not plugged
everything back in but when I found the sensor it was on the other end of
the engine from where he was working. Actually it was near where I worked
when I replaced the input speed sensor on the A/T.
More questions for HyundaiTech if you don't mind.
1) Do you see any way this could be caused by the crank sensor install work?
At this time I don't think I will go back to them with it,
2) Is this just another unrelated problem, like the crank sensor (P0335) and
input speed sensor (P0715) that popped up together. Or is there a bigger
problem looming here? I ask because we have spent over $1500 since the
problems started and sometimes you need to know when to cut your losses.
3) Am I on the right track to replace the ECT sensor? Any suggestions,
hints, watch-out-fors?
4) I do have the right sensor (ECT) I hope, its the one screwed into the
front side of (near) the thermostat housing, right?
5)Can I get a socket on it (over the connector) or must I use an open end
wrench?
6)This code can't be caused by a bad thermostat, can it?
Thanks

 

1. I can't think of any way this would be related to the crank sensor.

2. There's nothing that indicates that these problems are related in an
way. Since they're all unrelated, there's no way to predict from thes
failures how many future failures will occur or when they'll happen.

3,6. You're probably on the right track, but this code can also be cause
by a faulty thermostat or overheating.

If you have the capability of reading the freeze frame data, check th
coolant temperature in the freeze frame data. A very high temperatur
would indicate overheating. In this case, you should do a thorough chec
of the cooling system. A very low temperature (often -40) typicall
indicates a faulty sensor. A seemingly normal to a little low temperatur
often indicates a thermostat problem.

If you have no way to check freeze frame data, start with the coolin
system audit. If okay, then your chances are good with replacing th
sensor. If the thermostat isn't fairly new, I'd recommend replacing tha
as well. It doesn't cost much, is fairly easy to do, and it's better tha
having it fail later.

4. Sounds like the correct sensor. I believe it has three wires going t
it-- two for the PCM and one for the gauge.

5. It'll depend on the construction of the socket. Many deep socket
only have the hex on the bottom 1" or so, leaving a circular portio
toward the top. This circular portion typically won't fit over th
connector. A box wrench would be preferable to open-end. With open-end
you'll need to be *very* cautious about rounding the corners of th
sensor.

As a last tip, if you're replacing only the sensor, unpackage the new on
and have it ready in a place you can easily reach while working on th
car. Remove the radiator cap to release any pressure-- use extrem
caution if hot-- and reinstall. Then remove the old sensor and quickl
screw the new one into place. You'll lose only a very small amount o
coolant if you can get the new one started quickly.

 

Thanks Hyundaitech for you comments.
I replaced the ECT sensor and drove it enough so that I'm pretty sure that
it went into closed loop and no CEL came back on. Hope that's the end of
them for a while.
I was not able to use your suggestion on saving coolant. The old sensor was
a real bear to get out. I had to remove the hoses in order to get better
leverage and wrench angle/movement. I had a half gallon of AF laying around
to use.
The sensor only had two wires, on this engine there is a separate sender for
the gauge. The guy at the parts store tried to sell me the wrong part. He
asked me if the car had a gauge or a lite, that made me suspicious so I
looked at the part when he brought it out and it was the sender. He wasn't
paying attention and had clicked on sender rather than sensor. Computers
just let you make mistakes a lot faster.
One last question on this car
The engine hesitates when starting off cold (if 90 degrees outside can be
considered cold). Just doesn't seem to be getting/taking the gas quickly
enough. Makes me want to pull out the choke like in the old days. It seems
to be OK after a couple of miles.
It just had new plugs, coils and wires installed when the initial problem
was miss-diagnosed. It also had a "fuel system cleaning" done a couple of
months back. I think someone talked my son into that when he first starting
having problems with the car.
Anyway, what would you suggest as to where I should start looking.
Thanks

 

Wish there was a way to edit a post afterwards.
When I said it hesitates, what I meant was the engine seems to sputter and
even act as if it wants to stop but doesn't, but moves slowly. Finally it
picks up and moves on out normally.

 

There's a TSB regarding a reprogramming for something similar to what yo
describe. According to the TSB 03-36-019,

"The SONATA I4 reprogramming affects the following:

Infrequent minor engine hesitation after an initial cold start (typicall
the first start in the morning).
DTC P0139 (O2 Sensor Circuit Slow Response (Bank 1, Sensor 2)) chec
engine light illumination diagnosis revised. If this code is set and th
rear O2 sensor is diagnosed to be functioning normally, perform this EC
reprogramming procedure."

Expect this to be available at the dealer only

 

Couldn't find that TSB anywhere on Hmaservice.com
Not sure that it totally applies since there is no DTC P0139 as stated in
the TSB.
There are no codes set now (finally), nor pending.
In any case would Hyundai do the TSB on a car 9 years old with 91000 miles?
I did have the battery disconnected for a while, do you think that maybe
after the computer relearns some of its smarts that it may get better? Do
the parameters that it uses in open loop mode get modified as it relearns?

 

It's under the TSB section of Service Information --> Sonata(EF) 1999-->
FL - Fuel System.

The TSB was issued in 2003 for 1999-2002 Sonatas, so it's not that old.
I'm certain any Hyundai dealer would be willing and able to update
the programming in your ECM for their standard 1 hr diagnostic or
labor charge. TSB's are not recalls, they are just service bulletins for
the benefit of the service techs in diagnosing and solving problems
not covered in the usual service manuals. So your reprogramming
is probably a chargeable item, unless somehow it's covered under
the 10yr/100K warranty.

Bob

 

Dealer could get away with doing this under the 8/80 federal emission
warranty. Since you're at 91k, you'd have to pay for it.

It's doubtful that things would change with the relearns, but it probabl
can't hurt to wait a little bit and see.

The reprogramming was intended to address both a P0139 and the hesitation
but not all vehicles display both. The few vehicles I can recall needin
this displayed one or the other of the conditions

 

You're right Bob, its right there. I looked all over that section last nite,
they must have just added it today. ;-)

 

The reason I asked about the computer relearning is because I don't recall
this car having the problem before. I gave it to my son 5 years ago so I
haven't driven it much since. But I drove it for 4 years before that without
any problems. Maybe some part/sensor slowly failing over time, but which
one .. No codes set. Do I just have to wait for a solid fail? Its not
terribly bad in this hot weather, but I'm concerned that it will be much
worse when it gets cold.
thanks

 

Many hesitation issues are due to carboning of the valves. I'd suspec
that the reprogram alters the startup fuel mixture slightly to compensat
for this.

As for being worse when cold, if it's the hesitation referred to in th
bulletin, it should go away. The bulletin specifically referred to a col
start in warm ambient temperatures