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Discussion Starter · #1 ·
Let me preface this with the fact that I am not very knowledgeable about car repairs let alone VWs.

I've acquired a 2002 hatchback beetle that keep getting stuck in limp mode. I was told the ECU needed replacing and was given a replacement pulled out of a working beetle of the same model.

Question 1: how can I confirm this is the right ECU it has some serial numbers on it but no idea where to find if they're the right ones

Anyway I've got the new ECU in and the car starts for a second and goes out. Found out the immobilizer seems to be the issue.

Question 2: I think I just need a new key which can be programmed to the new ECU but I read there's a 3rd chip in the steering column. It stands to reason this chip will need to be replaced too?

How do I get her running again with her new ECU. Plugging the old one back in the car starts so I know it's the immobilizer shooting me in be foot. I'm trying not to have to empty out my pockets for no reason so I want to make sure I know exact what my next step is.
 

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5/23/10 <3
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I would be willing to bet that the ECU was not your problem. Do you know what codes were coming up for limp mode? You may end up dealing with the same problem with this new ECU.
 

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Anyway I've got the new ECU in and the car starts for a second and goes out. Found out the immobilizer seems to be the issue.

Question 2: I think I just need a new key which can be programmed to the new ECU but I read there's a 3rd chip in the steering column. It stands to reason this chip will need to be replaced too?
First let me say I'll second the idea that is wasn't the original ECU. There are basically 3 parts to the immobilizer, the ECU, the key and the instrument cluster. There is no "chip" in the steering column, but there is an antenna. It just gets the signal from the key. The key, cluster & ECU must be programmed together.
How do I get her running again with her new ECU. Plugging the old one back in the car starts so I know it's the immobilizer shooting me in be foot. I'm trying not to have to empty out my pockets for no reason so I want to make sure I know exact what my next step is.
If you really want to get the new ECU to work, you will need some specialized equipment or you will have to take it to a shop or dealer. You will need the new ECU programmed to your key & cluster (or maybe vice versa, but you get the idea). I suppose in theory if you had the key & cluster from the car the ECU came from you could swap everything and it may work, but I cannot confirm that. It will never run more than a few seconds with the new ECU until it is reprogrammed.

My suggestion is to reinstall the old ECU and try and sort out the codes and only replace the ECU if you are certain that is the problem. Furthermore, were I changing the ECU, I would send it to a tuner and have the immobilizer defeated. It generally runs about $100 and then will work in any (like) car with any key. No programming necessary.

I suggest you do a Google search for VW immobilizers and SKC codes and you will get a better picture of how the immobilizer operates.
 

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Discussion Starter · #4 ·
I would be willing to bet that the ECU was not your problem. Do you know what codes were coming up for limp mode? You may end up dealing with the same problem with this new ECU.
I'm not sure what if any error codes came up. To my understanding it was brought to a guy who only works on VWs professionally. He scanned it and couldn't come up with anything conclusive however based on his personal experience he had a high degree of certainty that it was the ECU. A used ECU was bought for it and the previous owner didn't want to put the time in to installing it since he had put time into replacing various other parts.

The car was hooked up to some tool to clear it out of limp mode, again I know little about cars, on the ride over. He could reset it and the car would run fine. The car can run perfectly for awhile before limping. It seems fairly plausible that it's computer related.

I believe it was an issue with some sort of Eco fule management. I can try to get more specific information but at the moment that's all I know.
 

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Discussion Starter · #5 ·
Anyway I've got the new ECU in and the car starts for a second and goes out. Found out the immobilizer seems to be the issue.

Question 2: I think I just need a new key which can be programmed to the new ECU but I read there's a 3rd chip in the steering column. It stands to reason this chip will need to be replaced too?
First let me say I'll second the idea that is wasn't the original ECU. There are basically 3 parts to the immobilizer, the ECU, the key and the instrument cluster. There is no "chip" in the steering column, but there is an antenna. It just gets the signal from the key. The key, cluster & ECU must be programmed together.
How do I get her running again with her new ECU. Plugging the old one back in the car starts so I know it's the immobilizer shooting me in be foot. I'm trying not to have to empty out my pockets for no reason so I want to make sure I know exact what my next step is.
If you really want to get the new ECU to work, you will need some specialized equipment or you will have to take it to a shop or dealer. You will need the new ECU programmed to your key & cluster (or maybe vice versa, but you get the idea). I suppose in theory if you had the key & cluster from the car the ECU came from you could swap everything and it may work, but I cannot confirm that. It will never run more than a few seconds with the new ECU until it is reprogrammed.

My suggestion is to reinstall the old ECU and try and sort out the codes and only replace the ECU if you are certain that is the problem. Furthermore, were I changing the ECU, I would send it to a tuner and have the immobilizer defeated. It generally runs about $100 and then will work in any (like) car with any key. No programming necessary.

I suggest you do a Google search for VW immobilizers and SKC codes and you will get a better picture of how the immobilizer operates.
Thank you this is very helpful!

As I responded above a professional seemed fairly certain it was the ECU but I'm no expert so I can only confirm what I'm told.

I don't have the cluster from the car the new ECU was taken from, would I have to buy a new one or would defeating the immobilizer be fine so long as I get a key programmed to match the cluster?
 

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5/23/10 <3
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I would put the original ECU back in and drive the car until it goes into limp mode. Then get the car scanned for codes and post up what you get (the actual code numbers, not just descriptions). Limp mode has a cause. The codes will tell you what that cause is. Limp mode is a protective mode for the car...something is going wrong and the car wants to limit the power going through it. Could be transmission related, turbo system related (if a turbo car), or several other things. Limp mode isn't usually caused by the ECU. I would hate for you to go through the trouble to get this new ECU working and still have the limp mode problem, which if the ECU isn't the culprit, exactly what will happen.

More info on the car...what engine? Transmission?
 

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Discussion Starter · #7 ·
I appreciate the help! I know the previous owner went through a list of parts that he thought it might be before he took it to the guy who works with VWs and suggested the ECU.

It's not a turbo I don't think, I'm not sure off the top of my head what's in it I'm at work now but maybe this picture will be of any use?

Vehicle Car Engine Auto part

I certainly don't have the tools to pull the error code but I'll see if I can find someone who does!

I'll try to put up more info tonight when I get home.


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I'm not sure what if any error codes came up. To my understanding it was brought to a guy who only works on VWs professionally. He scanned it and couldn't come up with anything conclusive however based on his personal experience he had a high degree of certainty that it was the ECU. A used ECU was bought for it and the previous owner didn't want to put the time in to installing it since he had put time into replacing various other parts.
I would question how much of an "VW expert" he is if he didn't know about the ECU and the immobilizer.

As stated, try and use the old ECU. I would only swap if you are certain that is the problem.
would defeating the immobilizer be fine so long as I get a key programmed to match the cluster?
If you go the immobilizer delete route any key or cluster will work - you will not need either programmed. It will totally eliminate the immobilizer. If you need a new key, all you have to do is get it cut and that's it. If you are going to keep the car forever, it actually is a worthwhile modification. But just to be clear, if you keep the ECU as is key (all keys if more than 1), ECU and cluster must be programmed to work together.
 

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As noted above; let's diagnose the problem correctly; before throwing a bunch of parts or ecu's at it. Do you have access to a scanner? If not; you should consider, purchasing a vw compatible scanner off of amazon.com. Search "vag scanner"; there are quite a few for less than $50 (e.g. vs450). Once you get the codes; post them up here and we will try to help you, then we can go from there.

PS: the engine you have is a non turbo 2.0L, 4 cylinder.
 

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Discussion Starter · #10 ·
Thanks for all the help guys, I'm working on getting my hands on a scanner now. Will update when I have codes to post!

As far as the guy who checked it out I'm sure he was aware of the immobilizer but the mechanic who I inherited it from probably didn't so never passed along the info. He's not savvy on the computer side of things which is why he wasn't up for the task of getting things in working order since it was just a side project. Enter me taking on the problem.


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