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Discussion Starter · #1 ·
I hope someone can help.


Elsewhere on the internet there is some advice about this problem, which seems to be fairly common on this model. But the advice is contradictory...



The fault is variable. Last Wednesday I drove nearly 200 miles and the car went like a dream. Yesterday, on a short journey, it kept on happening.



The transmission gives a slight "clunk" and goes down from fourth gear to third. And stays there. And the Engine Management Light comes on.




Sometimes the problem can be cured by stopping the car, switching off and waiting a bit. But yesterday I did this about five times, and each time the transmission quickly got stuck back in third.



Obviously I need a long-term solution. Has anyone here hadexperience of this fault? Did they get it cured? If so, how?
 

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Sounds like a pulse generator/input speedsensor, i think on that model it comes as a pair, sensor A and B, about £140 for the part, get it scanned for the DTC to double check
 

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Discussion Starter · #3 ·
Thank you for that ""“ and the good news is that your diagnosis is the same as the most credible of the (conflicting) advice I've read elsewhere on the internet.


I will have a word with my garage to suggest following this route, and will post back in due course to report the outcome...!
 

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Discussion Starter · #4 ·
Back again...






Problem is ... some people on other sites who've done this have found that this works ""“ and some haven't!



However it seems I can get the parts reasonably cheaply from the US:

[url]http://www.ebay.com/itm/230671710105?item=230671710105&viewitem=&sspagename=ADME:X:RTQ:MOTORS:1123&vxp=mtr[/url]

(Alternatively, the item is brought up by searching on eBay for
<H1 =vi-is1-titleH1 itemprop="name">SPEED SENSOR SET KIT INPUT OUTPUT OPTIMA SEDONA.)</H1>
<H1 =vi-is1-titleH1 itemprop="name"></H1>
<H1 =vi-is1-titleH1 itemprop="name">My inclination is to take a punt on these and ask my local garage to fit them.</H1>



Two questions:

1. Does that look like the right part? (Optima in US of course = Magentis in UK.)

2. Where are these things are located on the car! (In other words - easy job or long job...?)
 

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They are definatley the right parts and are located on top of gear box. You will need to remove airbox, battery and battery tray then just 2 10mm headed bolts.
 

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Discussion Starter · #6 ·
Many thanks, Mr Kia! Most helpful.


This incidentally was not information known to Hendy Kia in Cosham, who said they wouldn't be able to quote for the job until they'd seen the car, as they didn't know where the sensors went.



I know there aren't a lot of Magentises about, but you'd have thought that a Kia dealer's computer system might have the information on it somewhere...!
 

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Sounds like the car is going into limp home mode. Had the same thing on my old Nissan 240SX. It was caused by an out of tolerance throttle position sensor (TPS). Threw up about four codes.....none of them the TPS.
 

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Discussion Starter · #9 ·
Many thanks for that tip. I haven't yet ordered the speed sensors, so I'll ask my garage to have a look at the throttle position sensor before I do.






And will report back when I have further news on either front!
 

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Kia Aura said:
Many thanks for that tip. I haven't yet ordered the speed sensors, so I'll ask my garage to have a look at the throttle position sensor before I do.






And will report back when I have further news on either front!
They should be able to perform a simple resistance check - to verify if it is out of tolerance.
 

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The fact the vehicle gets stuck in gear is due to the speed sensors. You may also find that when you drve it and its not stuck in gear, it may seem to change gear at the wrong time ie; hold on to a gear like 2nd for longer than it needs to and revs higher???
 

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Found this info on the net which might help if you want to give it a go yourself?

Source: http://www.kia-forums.com/kia-magentis-optima-forum/35768-01-kia-optima-speed-sensor.html

So tonight I replaced the input and output shaft sensors and it was quick and easy. Here is a quick rundown of the procedure:



Loosen the bracket that connects the air filter box to the MAF sensor with a Phillips head screwdriver.



Open the air filter box with the four clips and remove the cover.



Remove the air filter.



Remove the 2-3 bolts (mine has 2 but there is a spot for a possible
third so maybe its just missing on mine) that hold the lower half of the
air filter box in place. The bolts are 10mm.



After removing the lower half of the air filter box you are looking down
at the transmission where you will see the sensors. I didn't take a
picture but if you have the spare parts on hand you'll recognize them.
Each sensor is held down by a 10mm bolt. One of the sensors, not sure
which one it is (the one further to the front of the car) has the bolt
covered up by the (not sure what this part is called) gear shift wire.
It is held down with two 12mm bolts.



Remove the two 12mm bolts and push the gear shift wire (someone needs to tell me what this thing is really called
)to the side.



Remove the connectors to the sensors and remove the 10mm bolts holding the sensors down. Pull the sensors straight up.



Push the new sensors in. Make sure you get the right one in the right
place. They look a little different, the connectors are facing in
different directions.



From here on its the reverse of the dis assembly.



Once everything is back together take the care for a test drive.
I read that you should drive it carefully so it shifts through all
gears and then the same procedure again with aggressive acceleration so
the computer can calibrate the new sensors. Not sure if that is true but
I did it and it drives nice and smooth.



The whole procedure took less than an hour and that with the help of a
toddler (my son always wants to help so it slows down a little but it
makes the little guy so happy
)

It cost me $89 total.



While I was in there I also cleaned the MAF and replaced the air filter.
Not only does the car shift again now I also got rid of a P0171 "engine
running too lean". I hope the engine light stays off now.
Edited by: gtd2000
 

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Discussion Starter · #13 ·
Thank you gtd2000 and Mr Kia for all this further very useful information.



I will present it allto my excellent small garage ""“ which has been looking after my cars for some 15 years ""“ and ask him to get stuck in. (This may not now be till after Christmas.)



One point. Mr Kia wrote: "The fact the vehicle gets stuck in gear is due to the speed sensors. You may also find that when you drive it and its not stuck in gear, it may seem to change gear at the wrong time ie; hold on to a gear like 2nd for longer than it needs to and revs higher???"



No ""“ the changing gear at the wrong time and the high-revvingdoes not apply in the case of my car. The only gear-box fault is that itjust gives a suddenjolt and goes into third and stays there. On a good day, if I stop, turn off the engine, fidddle about with the gears and wait a few minutes, it will then behave normally. On a bad day I can do this half a dozen times and the fault will keep returning.



(On avery good day I can drive 200 miles and the car will behave perfectly throughout.)
 

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Discussion Starter · #15 ·
Thank you, gtd2000, for your continuing interest.






The truth is thatthis problemis stillat the top of my list of things to sort out.



When the car behaves immaculately for a while (as it often does), I stick my head in the sand for a bit. Then, when it has a bad day, I realise that I reallymust get on and do something about it.



As soon as I do take action, I will of course report back here...



Your and Mr Kia's advice remains much appreciated and will not be wasted...!
 

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Was this ever sorted ?


My 02 Magentis has a similar fault



It wont change gear, from start up select drive and pull away and it wont change into 2ndbut using the tiptronic it will then thump into 3rd and the engine check light comes on and it will stay in 3rd unless i change down with the tiptronic to 2nd, but somtimes it works normaly changing gear as it should then without warning it will thump into 3rd gear and put the check light on



I bought the car like this and havent had it code read yet
 

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Discussion Starter · #17 ·
Your fault is identical to mine in every way.
As the various helpful posts indicate, replacingthe speed sensors should solve the problem.



Sometimes I can drive a hundred miles with no problem. But when the fault kicks in, it keeps kicking in. Sometimes it will cure itself if you stop the car, and then re-start it. More often it just clunks back into third again.



Oddly enough just two days ago I finally decided I must get the parts and get the problem sorted out. I think the partsare much cheaper from America, even with postage and UK import taxes.



http://www.ebay.com/itm/230671710105?item=230671710105&viewitem=&sspagename=ADME:X:RTQ:MOTORS:1123&vxp=mtr



As you probably know the Magentis of that era was called the Optima in America.



I wrote to ask the eBayseller if these were right for my car.



He replied:

"yes these will fit those models , but
on about 10% of international models the sensor's contain (2) Two pins inside the connector
our sensors are the (3) Three pin design
it's always a good idea to glance at the ones on your model to confirm the pin count"



So this obviously needs to be checked.


I'll report back if / when I make any progress, and it would be appreciated if you would do the same!
 

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Had a look today the sensors are right under the air filter box






Sensors are arrowed







both are held by a single 10mm bolt but to get them out the wiring needs to be released from the n/s inner wing and the selector cable bracket needs to come off .



I removed both sensors they are the 3 pin type cleaned them and refitted them built it all back up put the battery back on the car drove perfectly for2 miles then thumped into 3rdcheck light came on , but i did notice while it was working the display on the dash diddntcoincide with the gear changes



Next step is get the codes read but i havent got time to do that until the weekend
Edited by: Stixy
 

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Discussion Starter · #19 ·
That's very helpful.


My car is looked after by my (excellent) small garage, butI'll have a word with him and e-mail him the link to this page if he'd like to see the pictures.
 

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Read the fault codes and got


P0720 = output speed sensor circuit

P1529 = request from Transmission control unit to Engine control unit to activate the CHECK lamp



So sensors ordered from the States so just waiting for them to arrive now
 
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