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OBD II scanner reading Link Connection Error

20K views 6 replies 3 participants last post by  Mdoyle4711 
#1 ·
A few weeks ago I had a check engine light come on and hooked it up to my OBD II scanner and it gave me a link connection error on the screen. So I stopped by an advanced auto parts store and had them check it with their OBD II scanner and received the same exact thing. So fortunate for me I was on my way to a dealership to have recalls done on it and had them check the light and they said they couldn't connect to the cars computer and that it had to be something feeding back into it.

So long story short they did tests on the car for almost the whole day with no results except a frayed wire that they said they found and replaced which costed me $400 and they said they hard reset the car to see if that would fix the check engine light issue. Two weeks later the light has come on twice since then and when connected to an OBD II scanner reads the same link connection error. What gives? Could this be a bad computer?
 
#4 ·
Could this be a bad computer?
Well, it could be a bad computer but isn't that what you paid the dealer for? To diagnose the problem and tell you what was causing it?

The post at the link below is from a guy who put his Santa Fe into the dealer to have a diag tool link error diagnosed. The dealer wanted to replace his computer for a cool $1500...with no guarantee that the new computer would cure the problem. Luckily, he came to the forum for advice before going ahead with the repair and we managed to help him diagnose and fix the problem. Needless to say, the $1500 computer wouldn't have cured the problem.

you might find some useful fault finding tips in that post that might help with your problem. Maybe print it out and give it to your dealer :laugh:

Santa Fe - Emissions Machine No Comms With Car Computer
 
#5 ·
Could this be a bad computer?
Well, it could be a bad computer but isn't that what you paid the dealer for? To diagnose the problem and tell you what was causing it?

The post at the link below is from a guy who put his Santa Fe into the dealer to have a diag tool link error diagnosed. The dealer wanted to replace his computer for a cool $1500...with no guarantee that the new computer would cure the problem. Luckily, he came to the forum for advice before going ahead with the repair and we managed to help him diagnose and fix the problem. Needless to say, the $1500 computer wouldn't have cured the problem.

you might find some useful fault finding tips in that post that might help with your problem. Maybe print it out and give it to your dealer


Santa Fe - Emissions Machine No Comms With Car Computer



The engine light did go off for a couple days and then came back on yesterday and is now off again. Plus I have the parking brake light on and the abs light on and those flash simultaneously. The Hyundai dealership where I live said they couldn't isolate the issue and don't know what could be causing the issue. Any ideas?
 
#6 ·
Any ideas?
My guess is there's a problem with the car's CAN BUS....the computer network that links the engine and ESP control modules . The OBD scan tool communicates with the engine PCM over the data bus too so that would seem to explain all the warning lights and the comms link error.

Unfortunately, CAN faults are difficult to diagnose DIY....unless you have an oscilloscope. But there are a couple of simple test you can do with a mutimeter.

You can measure the voltages on the CAN terminals of the OBD connector. Connect your black meter probe to a good ground and touch the red probe to the CAN HI terminal....see below. With the ignition on you should see approx 3V. Measuring the voltage on CAN LO should show approx 2V. The other test you could try is disconnect the battery and measure the resistance across the two CAN terminals. You should get a reading of approx 60 Ohms. If you get 120 Ohms, one of the CAN wires is open circuit. If you get zero Ohms, the two CAN wires are shorted together.

I hope that helps.

Scott.

 

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