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Discussion Starter · #1 ·
I own a 2005 Santa Fe 3.5L. I took it to 3 different places for emissions but was told their machines could not read the car computer - no code, no error - basically they wouldn't shake hands. I have checked to see if there were any blown fuses but there was none. A new radio was installed last October so I removed the new radio, reinstalled the old one just to see but no success either. I took it to the dealership and after waiting for 3 long hours, I was told they had no idea either. The car runs great without any issue and the only suggestion they had was to replace the computer at $1,500.00 but there would be no guarantee either. Anyone has any idea what could be wrong? Thank you in advance!
 

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Nice of your dealer to offer to relieve you of $1,500 with no guarantee that your fault will be fixed.

What I suggest you do before parting with your $1500 is get a voltmeter and check that you have a power supply & ground to the diagnostic connector (the DLC).

First connect the black meter lead to a good ground then touch the red probe to pin 16 of the DLC and make sure you get 12V.
Next, with the red probe touching pin 16, touch the black probe onto pin 4 then pin 5 and again make sure you get 12V on each.

Scottie.
 

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USA model, the sunroof fuse drives the "+" at the DLC..

-- " I have checked to see if there were any blown fuses but there was none." --


What did we use to check with ??

This is how we test fuses and circuit --
 

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Discussion Starter · #4 ·
Thank you both for your replies!

I also use the multimeter to test the power.

Scottie, I followed your direction and retested the power (although I had already done so previously) just to make sure but everything is normal. What else can I do from this point? I am willing to pay $1,500 to have the computer replaced but without guarantee, I am hesitant to do so. My car needs to pass inspection by the end of June or I would not be able to drive it on the road. Any help would be greatly appreciated!
 

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topmack, does your vehicle have a factory immobilizer system?

On UK models the K-line (the communication wire between the DLC and the engine PCM) doesn't route directly between the engine PCM & the DLC. It first passes through the immobilizer control module (the ICM). Inside the ICM there is a relay that should switch the K-line from the engine PCM over to the wire coming from the DLC when the scan tool is connected (see attached). If the relay fails to switch over for whatever reason, the scan tool can no longer communicate with the engine PCM. You could re-establish the link by manually bypassing the ICM.

I don't know if that is relevant to your vehicle but I think it's worth looking into before trashing the $1500 PCM.

Scott.
 

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Discussion Starter · #7 ·
Scott,

Mine doesn't have that. I do appreciate your reply! I will have to figure out something else quick or make a decision whether I want to take a risk of having the computer replaced with no guarantee.

Tom
 

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What could be wrong? You haven't indicated a problem except you can't get the code reader to connect. Sounds to me like you need to stop disconnecting power to the ecu. Every time you hard boot the ecu, it takes numerous drive cycles for the thing to completely reset emissions data and make a reading for the code reader. I'm sure the dealer would be overjoyed to replace your ecu for $1500, they make a fortune replacing a part with a 5 minute install. I got an idea... fugetaboutit.
 

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I got an idea... fugetaboutit.
Can you do that though?

We have different emission tests here in the UK so I may be wrong here, but in the US don't they need to connect a tool to the DLC as part of the emissions test? Surly if they're tool can't link with the engine PCM, the car wouldn't be able to pass the test?

topmack, have you checked to see if there is any voltage on terminal 7 of the DLC when the ignition is switched on? If you don't have any voltage present then another thing you could check is the K-Line on the check connector behind the driver's dash trim. There is a K-Line terminal on Pin 7 of that connector too. It's a white male connector with, usually, 8 terminals...see attached. If you find you have no voltage on terminal 7 of the DLC but 10~12V on pin 7 of the check connector, you could try linking a wire between the two connectors and see if that restores comms with the engine.

Scott.
 

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What about cleaning the contacts on the DLC connector and the PCM connectors with contact cleaner? Would that be worth trying? AUTOSPARK: thanks for the detailed posts, you are giving us DIYers a real education in how to perform diagnostics.
 

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Discussion Starter · #12 ·
Thank you guys for the replies! Scott, you are correct! if the tool can't link with the engine PCM, the car wouldn't be able to pass the test. The diagram you attached is a 2002 Kia diagram. It doesn't look the same as the Hyundai's. Did I misunderstand you?

To answer your question, jsinton, I did not keep disconnecting power to the ECU. In order to troubleshoot it, I had to test to see if there were any blown fuses. And then the aftermarket radio question came up, so I had to disconnect the radio to see if that was the issue. After that, I took it to the dealer to have them troubleshoot it. I do not wish to pay the dealer $1,500 either; that is the last thing I want to do, especially when the car runs great.

I do appreciate everyone for their replies!
 

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Yeah, the diagram was from a Kia, but a Kia is just a Hyundai in disguise.

hyundai/Kia cars have two diagnostic connectors. The standard 16 pin OBD DLC and that other one. It will be behind the driver's side dash trim in the area around the fusebox.
 

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Discussion Starter · #14 ·
Scott,

Although the diagram is not the same, I am following your instructions and test your theory. I will post the outcome as soon as I am done. I truly appreciate someone like you who takes the time to answer other people's problems. I will keep you posted.

Tom
 

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Discussion Starter · #15 ·
Scott,

I checked and there was no voltage on terminal 7 of the DLC when the ignition was switched on. I then proceeded to check the K-Line on the check connector behind the driver's dash trim. Pin 7 showed 8.6V but not 10-12V but I went ahead and linked a wire between the two connectors, as you suggested. I then connected the OBD scanner and viola, it said "pass". I immediately took the vehicle to the emissions place and it PASSED the inspection!!!!!

I cannot thank you enough for your help. Your BS evidently wasn't BS; you have saved me $1,500.00! I do have one more question if you don't mind. What was in the circuit that could have caused the voltage not be on the pin? Just wondering if I need to find a permanent fix to the problem, but again, THANK YOU!

Tom
 

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I cannot thank you enough for your help. Your BS evidently wasn't BS; you have saved me $1,500.00!
I'm glad I was able to assist you, Tom. It makes me wonder what is going on in the Hyundai dealerships these days though? I don't see why they couldn't figure out how to do that when they have the car right there in front of them yet I could sus it out from half way round the globe. There was a guy on another thread the yesterday who had a problem with his Elantra and his dealer had it for more than two hours and could figure out why the clock & interior lamp wouldn't work. I told him to replace the ROOM LP fuse...sorted! honestly, what is going on?

I do have one more question if you don't mind. What was in the circuit that could have caused the voltage not be on the pin?
The two K-Line pins on the two connectors are linked in the vehicle loom. The only difference is on cars that have the factory immobilizer. The K-Line on the 16 pin DLC routes through the immobilizer like I explained before as where the K-Line on the 10 pin check connector routes direct from the PCM. So, if your car doesn't have an immobilizer, I don't know why there should be no voltage on the K-Line the 16 pin DLC. Either way, you can simply link the two connectors permanently. I don't see any problem with doing that.

Regards.

Scott.
 

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Discussion Starter · #18 ·
Scott,

I also asked the same question over and over again. These are mechanics who should possess the knowledge that I don't have but the only solution they could offer was to replace the computer. Anyway, I will leave it the way it is if you think it's ok. I truly truly appreciate your assistance!
 

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And.....on top of that, I think replacing the computer would not have solved the problem in this case.
No, clearly it wouldn't have solved the problem. Not that they would care too much. I'm sure they make a decent mark up on the replacement PCM. And no doubt they would want to charge you even more labour to try and diagnose what the real cause of the problem was.

All the best.

Scott.
 
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