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2003 Sonata 2.4 Weird Transmission

18K views 25 replies 8 participants last post by  bornblonde63 
#1 ·
Hey there guys and gals.

I have a 2003 Hyundai Sonata 2.4L automatic with 133.000Km (83.000 miles) on it.
I bought the car at 82.000Km (51.000 miles).
About a month or two ago I went and changed my transmission oil.Everything was good but a few weeks ago the car started to act weird.
For example when I get of a ramp to get on the highway and start to give it more gas to enter the traffic the car will take a few seconds before it speeds up.
When you give it gas it takes a bit to react and then it down shifts and increases the RPM all the way up to 2700-3000RPM and then it goes.
Another example is when I'm in traffic and I move really slow the car will move then I brake only a bit and press on the gas again the car will jerk and then change gears and go.
It's kind of annoying for a car with this millage to have transmission problems.I'm the second owner and before me it belonged to a old gentlemen.
I also added some Trans-Medic in the transmission but no difference.
I went to my mechanic and he told me that it might be the computer and it might need a resofting and that only the dealership can do.
I really want your opinion on this because I'm sure the dealership will pop out some crazy thing like I need a new transmission or something like that,that will cost me a arm and a leg to change
plus if I pay $1500 for a transmission is not worth because I will never get back that money.


Please let me know if you need more details and I will be more then happy to add them.

Thank you in advance to all of you that took the time to read and answer :thumbsup:

PS:If I use the Tiptronic the car works flawless without any jerks or anything.
 
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#4 ·
QUOTE (jsinton @ May 28 2010, 07:56 PM) index.php?act=findpost&pid=327533
So where did you have the trans fluid changed? Did they use the correct fluid?

Do you have a check engine light? Did you do a code scan?

Hi and thank you for your answer.
My mechanic changed the transmission oil witch was bought from Hyundai dealership.
No there is no check engine light on and we did not do any code scans.
There's no warning light on or anything its only the way the gears are changed.
I was reading on a website about resetting the TCM or something like that (I'm not a mechanic so sorry if I'm talking about something different)
 
#5 ·
If it was my car, at this point I would drain the fluid and drop the pan. I suspect you're going to find some metal bits in there. If no metal in the pan, and no trouble codes, then maybe it's something else like the TPS or low fluid, etc.

Stay away from products like Trans Medic, not a good thing to do.
 
#6 ·
Hey Al,

I had this problem on my 2004 Sonata 4-cyl auto around 120k miles. I replaced the Input and Output Speed Sensors on the transmission and it fixed it. They are located on the top of the transmission case (driver's side of car). It's hard to see them without taking off the air intake. You may need to take out the battery to get to all the bolts on the intake as well. They are not difficult to replace, however it was tough for me to get the connectors apart without breaking them, so I had to replace those as well. Let us know if that was it. Here is the link I followed. FYI, there are two pages so look for the next button near the bottom; it's almost hidden.

http://www.google.com/imgres?imgurl=http:/...4PmHoWKlwfa6oQE



Thanks,
Kyle
 
#7 ·
QUOTE (jsinton @ May 29 2010, 12:10 AM) index.php?act=findpost&pid=327559
If it was my car, at this point I would drain the fluid and drop the pan. I suspect you're going to find some metal bits in there. If no metal in the pan, and no trouble codes, then maybe it's something else like the TPS or low fluid, etc.

Stay away from products like Trans Medic, not a good thing to do.

NGT has no bottom pan.... just the drain plug..

Scan the thing, both PCM and TCM for DTC.... Report back.
 
#8 ·
Hey guys thank you for your answers.
Most probably the input or the output sensor doesn't work properly anymore.The problem is that here in Canada if I go to the dealer to have my car scanned will cost me over $100 witch I find absurd so I will just go ahead and change the sensors.
I would prefer not changing both and only the output to see if the car starts working normally and after if it doesn't work I will proceed with the input too.
I just got of the phone with the Hyundai Dealership and I was told they cost $244+tx/each. :blink: So for both with tax will be around $550 and I will have to change them myself.
What do you guys think should I go and change the output first and then if nothings different change the input too?

Thank you again for your time and answers.I appreciate it
 
#9 ·
QUOTE (al3x3y @ Jun 2 2010, 10:25 AM) index.php?act=findpost&pid=328795
Hey guys thank you for your answers.
Most probably the input or the output sensor doesn't work properly anymore.The problem is that here in Canada if I go to the dealer to have my car scanned will cost me over $100 witch I find absurd so I will just go ahead and change the sensors.
I would prefer not changing both and only the output to see if the car starts working normally and after if it doesn't work I will proceed with the input too.
I just got of the phone with the Hyundai Dealership and I was told they cost $244+tx/each. :blink: So for both with tax will be around $550 and I will have to change them myself.
What do you guys think should I go and change the output first and then if nothings different change the input too?

Thank you again for your time and answers.I appreciate it
You should be able to to have you car scanned for free at Canadian Battery or someplace. That would rule out or not your input/output sensor theory. In a pinch, you should be able to buy a scanner yourself for under $100. We just need the codes to give you a better answer. Without the codes you're just shooting in the dark.
 
#11 ·
QUOTE (al3x3y @ Jun 2 2010, 10:57 AM) index.php?act=findpost&pid=328808
Any scanner can give me the codes that I am looking for?
Will this scanner be able to give me the codes?
http://www.canadiantire.ca/AST/browse/4/Au...r.jsp?locale=en
I think cars from 2004 are compliant with the CAN standard (not to be confused with CANada), so I think any old ODB II scanner will work. But just to be on the safe side, I think I would get a scanner which is CAN compliant. I'm sure your scanner from Canadian Tire will work, but they look a little pricey. I would probably be tempted to buy this one:

http://cgi.ebay.ca/ODB-2-Auto-Scanner-Tool...3#ht_5619wt_704
 
#12 ·
QUOTE (jsinton @ Jun 2 2010, 09:20 AM) index.php?act=findpost&pid=328833
I think cars from 2004 are compliant with the CAN standard (not to be confused with CANada), so I think any old ODB II scanner will work. But just to be on the safe side, I think I would get a scanner which is CAN compliant. I'm sure your scanner from Canadian Tire will work, but they look a little pricey. I would probably be tempted to buy this one:

http://cgi.ebay.ca/ODB-2-Auto-Scanner-Tool...3#ht_5619wt_704

I got a more expensive scanner and still nothing.I have 0 codes plus I need to get it fixed ASAP because I do a lot of millage every day with the car.
The problem is that the only in and output sensors at a resonable price are on eBay witch will take a week if not more to receive.
 
#13 ·
If you were having problems with your input or output sensors then you would have codes. I don't recommend you replace them unless you get those codes. Also, other trans problem too... I would expect to see some codes if you had a trans problem.

Since you have no codes, then you have to look for other problems. Fuel problems are a good candidate with no codes.

What do you mean when you say "enter the traffic the car will take a few seconds before it speeds up"? Is the trans slipping, or is the motor not reacting? Sounds to me more like your motor is bogging down and the transmission is trying to compensate by changing gears?
 
#14 ·
You will not get TCM codes using a scanner that only scans PCM codes... You need to pay somebody with hardware to access the TCM for DTC(s) if any stored.... :thumbsup:
 

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#16 ·
QUOTE (jsinton @ Jun 2 2010, 02:45 PM) index.php?act=findpost&pid=328884
He would get transmission codes in the P0700 to P0899 range, like P0715 for input sensor or P0720 for output sensor, etc.
Provided scanner/reader used has software to break into the seperate TCM to find them codes.. Thats why we have the 1529 which is a TCM request for the PCM to illuminate the MIL so we know there is a malfunction that needs inspect... I find a 1529 Mil request from TCM code in the PCM, I know to go to the Transmission control and scan there for DTC..

I been doing OBD-II since it came out in 1995 (pre Federal mandate with Toyota)
 

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#17 ·
I have what sounds like the same prob and has been happening off and on for months. Check Engine Light finally came on and the code was for the Throttle Position Sensor. Bought a new one for $90 (American) and replaced it myself and did not help at all. The car has a spot on the accelerator where if I'm under that spot it feels like I just kicked a manual transmission into too low a gear for the speed I'm going (although the RPMS stay at about 1.5k) and if I'm above that spot the RPMS jump up to about 3k-3.5k and the car takes off. I'm about to replace the fuel filter and reset the ECM, but would like to know if there's anything else I can try.
 
#18 ·
Hey guys sorry for the late reply.
I had the car scanned with a more advanced scanner and still nothing showed up.I have my input and output sensors on the way so after I get them changed I will report back.

You guys helped me a lot in trouble shooting my problem.
The parts should be here by the end of the week and after they get changed I will let you guys know how things go.
 
#19 ·
QUOTE (al3x3y @ Jun 7 2010, 09:29 PM) index.php?act=findpost&pid=330739
Hey guys sorry for the late reply.
I had the car scanned with a more advanced scanner and still nothing showed up.I have my input and output sensors on the way so after I get them changed I will report back.

You guys helped me a lot in trouble shooting my problem.
The parts should be here by the end of the week and after they get changed I will let you guys know how things go.

I bought my sensors on ebay for under $100 and they got here in two days. I'm not sure why they are so expensive from the dealer but I would consider returning them and getting them from the guy I did on ebay. The guy I got them from had 100s of OEM hyundai parts. By the way, my car was not throwing a CEL when I had this problem either. Good luck:)
 
#20 ·
QUOTE (TEG_FAN @ Jun 11 2010, 06:55 AM) index.php?act=findpost&pid=331989
I bought my sensors on ebay for under $100 and they got here in two days. I'm not sure why they are so expensive from the dealer but I would consider returning them and getting them from the guy I did on ebay. The guy I got them from had 100s of OEM hyundai parts. By the way, my car was not throwing a CEL when I had this problem either. Good luck:)

Thank you for your reply.
I bought my parts on eBay too I couldn't pay that much at the dealer.
Its been a week now since he sent them but Canada Snail Mail takes forever to deliver them.Still waiting for them I will report back after I get them installed.

Have a good one guys and galls :)
 
#21 ·
Hi there guys and sorry for the late reply.I finally got my parts Friday and managed to install them yesterday.
It took me 45 minutes to do it and everything works just fine.
The car is running like new and I'm a happy camper again :)
I want to thank all of you for the support and for the quick reply's.
I wish you the best of luck and see you around the forum.:)
 
#22 ·
I realize this post is fairly old, but I am having the same problem with my Sonata. It doesn't throw out any codes either. From everything I've read, the input and output sensors are the most likely culprits. The blog link in one of the posts by TEG MAN http://www.google.com/imgres?imgurl=http:/...4PmHoWKlwfa6oQE
did not allow the pictures to show up. Unsure of why, and the blog only talks about the input sensor replacement. Would someone be able to describe for me where these sensors are located and how to get to them? I've never worked on automobiles, besides changing out the headlights (which needs to be done a lot on my sonatas). Dialysis machines are my forte, so I am technically and mechanically adept. Thank you in advance for any advice/instruction you can give me!

*Amber*
http://www.google.com/imgres?imgurl...tive&gbv=2&tbs=isch:1&ei=p0PQS4PmHoWKlwfa6oQE
 
#23 ·
I wanted to update this post. It seems my sonata has been fixed. I found a thread about disconnecting the negative terminal of the battery, then reconnecting and then driving the car @25% throttle, allowing the car to move through all the gears. I did it twice while on a back country road and it has been symptomatic free since Memorial day! Since having to remove the battery to get at the input/output sensors, I would suggest trying this first. Thank you Hyundai Forums for allowing those of us with little knowledge to pick your minds!
 
#24 ·
HI I had what I thought was a slipping trans, took it to the transmission shop. where I live the temps are 3 digit in the summer time, with the air and lights and radio I was over working the altenator. I will be changing it out to a new one, this one is not putting out enough amps. the shifting valves need good even power to shift the trans down, winter time trans works great, I need a new battery to its not keeping full charge.
 
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