2.5 ECU Swap/Coding |
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TEADUNKER
Newbie Joined: 12 Nov 14 Location: United Kingdom Status: Offline Points: 6 |
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Posted: 27 Feb 17 at 14:43 |
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Hi,
Can anyone on here tell me anything about ECU coding to the vehicle? I want to swap the ECU out on my van as I've got a problem and I want to eliminate it (or confirm it) as the cause. Can the ECU be coded to the vehicle with VAG-COM / VCDS or does it need something else? Can anyone tell me how it's done? The van is a 2009 T5 2.5 BNZ manual. Thanks in advance.
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T5 TDI
Vanorak Joined: 05 Nov 05 Status: Offline Points: 3687 |
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I'm fairly sure can but you will need to make sure your donor ECU is exactly the same part number and that you have the four digit key code/pin for both ECU's. If you are missing either, VCDS can't extract them and you will need an auto locksmith or someone with Vag Tacho kit or similar.
I think my old 2004 van is immob 3 and the immobilizer is located in the instrument cluster, yours is probably the same but I'm not certain. You will need to swap over the coding and adaptions from the old ECU first. Read this- http://wiki.ross-tech.com/wiki/index.php/Immobilizer_III_ECU_Swapping Edit- What is the fault? Any fault codes?
Edited by T5 TDI - 27 Feb 17 at 16:05 |
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2004 2.5 174
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TEADUNKER
Newbie Joined: 12 Nov 14 Location: United Kingdom Status: Offline Points: 6 |
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Cheers.
I've found a few second hand ECUs with the same part number for around £150-200. I'm willing to buy one at that price and if it doesn't fix the problem (but does work) I can sell it on and hopefully not lose much. I had a feeling that it might need VAG-Tacho. So, am I right in thinking that I need VAG-Tacho to read the PIN number and then I can use VCDS with that PIN number to pair the ECU with the immobilizer? Would I definitely need the PIN from both ECUs, not just my original PIN to code into the new one? Edit: It's an intermittent starting/stalling fault. The ECU has been tested but as it's an intermittent problem I can't rule it out yet. My mechanic has had a scenario where they had an ECU tested and came back as OK but when they swapped it out, the fault disappeared (after months of head scratching and testing other bits). As it's intermittent it's tricky to find the fault and there are no relevant fault codes. A number of things have been ruled out (injectors, pumps, wiring). It's looking possible that it's worn injector bores.
Edited by TEADUNKER - 27 Feb 17 at 16:15 |
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T5 TDI
Vanorak Joined: 05 Nov 05 Status: Offline Points: 3687 |
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Yes but if you have access to VAG-Tacho you could do the whole job with that.
When you connect the second hand ECU up it will still remember its old van in quite a few ways. Chassis number and mileage and certainly immobilizer. So unless you can provide the pin to prove you are 'genuine' it will not play ball.
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2004 2.5 174
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gregozedobe
Vanorak Joined: 22 Dec 06 Location: Canberra, Oz Status: Offline Points: -998266 |
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Has anyone looked at cranking RPM when trying to start the engine. If the ECU believes the starter motor is cranking too slow the ECU won't allow fuel injection to begin so the engine won't start. IIRC VCDS can show the cranking RPM.
Most common reason is dud battery not supplying quite enough amps and volts during startup, but starter motors have also been known to be at fault, and then there is also the possibility of wiring problems (including earths). These areas might be worth investigating first (if they haven't already been properly checked out) as it is easier than swapping ECUs and recoding immobilizers.
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TEADUNKER
Newbie Joined: 12 Nov 14 Location: United Kingdom Status: Offline Points: 6 |
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Thanks T5 TDI, it sounds like it might be a bit of a nightmare. I don't expect a breakers yard selling a second hand ECU will be nice enough to supply the PIN code so I might have to think of something else.
Gregozedobe, thanks for the suggestion. I'll mention it to my mechanic. I expect he's checked but it's worth checking. It wasn't noticeably cranking slowly but it might only be obvious with VCDS.
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