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Nazzywazzy

Changing an ECU?

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Hey everyone, 

I have a 2000 1.4 Lupo that needs a new ECU. I was thinking about buying a second hand one and fitting it myself. Would this be really tricky? I have read that you may need to get it recoded from the dealer etc. is this actually the case? 

Thanks in advance :)

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Why does it need an ECU?

They rarely rarely go wrong but are often diagnosed so you leave the diagnoser alone.

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Also, I would buy an ECU with the key and immob box and do it that way.

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56 minutes ago, Rich said:

Why does it need an ECU?

They rarely rarely go wrong but are often diagnosed so you leave the diagnoser alone.

My lupo struggles to start intermittently and has lots of electrical faults (central locking not working, problems with the stereo etc. When I diagnosed it there was various short to ground faults. My mechanic checked over all the wiring to see if there was any corrosion or a bad earth and all was fine he said he was 95% sure it's a problem with the ECU 🤔

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56 minutes ago, weslangdon said:

If you have a TDI I have a spare ecu, but it will need coding to your car

Thank you for the offer but I don't have a TDI 😔

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17 minutes ago, Nazzywazzy said:

My lupo struggles to start intermittently and has lots of electrical faults (central locking not working, problems with the stereo etc. When I diagnosed it there was various short to ground faults. My mechanic checked over all the wiring to see if there was any corrosion or a bad earth and all was fine he said he was 95% sure it's a problem with the ECU 🤔

That sounds like ****. If the central locking isn't working, i can't see why that's got much, if anything to do with the ECU. It is controlled by the CCM.

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27 minutes ago, Skezza said:

That sounds like ****. If the central locking isn't working, i can't see why that's got much, if anything to do with the ECU. It is controlled by the CCM.

Tbh I don't care about the little faults like the central locking etc. It's the starting issues that are causing a problem. Right now my car is stuck in my local supermarket car park as it didn't start after an hour of trying this afternoon 😔

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I'll stick my neck out and say definitely not the ECU. Convenience control module (CCM) may have a link to windows and locks as already mentioned, but most likely the lock microswitches in the door.

non starting means probably no fuel injecting or no ignition sparking. The ECU uses the crankshaft sensor as it's primary sensor to get the ignition to go; and water temp/MAP/MAF/air temp to work out how much fuel to throw in. Assuming fuel pump is running ok...

diagnostics will tell all...

the stereo not working makes me think a power relay or perhaps ignition key switch?

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I had a 1.4 with starting issues.

Was the crankshaft.

Go try it now it is cold and it should work.

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17 minutes ago, mk2 said:

I'll stick my neck out and say definitely not the ECU. Convenience control module (CCM) may have a link to windows and locks as already mentioned, but most likely the lock microswitches in the door.

non starting means probably no fuel injecting or no ignition sparking. The ECU uses the crankshaft sensor as it's primary sensor to get the ignition to go; and water temp/MAP/MAF/air temp to work out how much fuel to throw in. Assuming fuel pump is running ok...

diagnostics will tell all...

the stereo not working makes me think a power relay or perhaps ignition key switch?

 

15 minutes ago, Rich said:

I had a 1.4 with starting issues.

Was the crankshaft.

Go try it now it is cold and it should work.

Thanks guys, you've both been extremely helpful. Funnily enough, the car never struggles to start in winter...

The diagnostic said something about the fuel injectors, here's exactly what it picked up:

Address 01: Engine       Labels: 036-906-014-AHW.LBL
   Controller: 036 906 014 BLw
   Component:  MARELLI 4CV       2802
   Coding: 00003
   Shop #: WSC 01236
   VCID: D2D7794B0DF7
5 Faults Found:
01249 -  Fuel Injector for Cylinder 1 (N30)
            29-10 -  Short to Ground - Intermittent
01250 - Shareware Version. To Decode all DTCs
            29-10 - Please Register/Activate - Intermittent
01251 - Shareware Version. To Decode all DTCs
            29-10 - Please Register/Activate - Intermittent
01252 -  Fuel Injector for Cylinder 4 (N33)
            29-10 -  Short to Ground - Intermittent
01312 - Shareware Version. To Decode all DTCs
            37-10 - Please Register/Activate - Intermittent
Readiness: N/A

-------------------------------------------------------------------------------
Address 02: Auto Trans       Labels: None
   Controller: 001 927 749 G
   Component: AG4 Getriebe 001    2022
   VCID: 1E4F5D7B89AF
No fault code found.

-------------------------------------------------------------------------------
Address 15: Airbags       Labels: 6Q0-909-605-VW5.LBL
   Controller: 6Q0 909 601
   Component: 02 AIRBAG VW5       0003
   Coding: 12338
   Shop #: WSC 01236
   VCID: F093D3C3A3BB
1 Fault Found:
00532 -  Supply Voltage B+
            07-10 -  Signal too Low - Intermittent

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So shorts on one and four 

That wouldn't stop it starting.

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3 hours ago, Nazzywazzy said:

Thank you for the offer but I don't have a TDI 😔

There are 3 types of 1.4 litre Lupo, a 75bhp petrol, a 100bhp petrol and the TDI

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Well I'm assuming this is a 75 version.

Does it crank when you turn the key?

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Its a power relay failure... ecu thinks there's a short. Reality is there's no volts.

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I don't know why..... But I'd be interested to see what happened if you tried jump starting it off another car with a good battery.

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Pull the plugs off the ecu and look for dark corroded pins and connections there as well.

That is all 4 injectors not working so check their wiring loom too.

If you have to take it somewhere then take it to an auto electrician as opposed to a mechanic due to specialist knowledge, so it will be less guess work.

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Where are you based? I have recent ecu fun experience if I can help in any way xx

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Thanks for your help everyone.

10 hours ago, Rich said:

Well I'm assuming this is a 75 version.

Does it crank when you turn the key?

It does crank when I turn the key, but just doesn't fire up. But yesterday afternoon, it cranked, fired up and then immediately cut out and wouldn't start again! 

7 minutes ago, loopydebs said:

Where are you based? I have recent ecu fun experience if I can help in any way xx

I'm based in Bristol! X

47 minutes ago, Skezza said:

I don't know why..... But I'd be interested to see what happened if you tried jump starting it off another car with a good battery.

I have thought about that, I'll give it a try next time it happens. 

44 minutes ago, Sausage said:

Pull the plugs off the ecu and look for dark corroded pins and connections there as well.

That is all 4 injectors not working so check their wiring loom too.

If you have to take it somewhere then take it to an auto electrician as opposed to a mechanic due to specialist knowledge, so it will be less guess work.

Thank you, good shout taking it to an auto electrican rather than a mechanic. 

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ahh I’m nowhere near you sorry! Hope you get it sorted, it’s such a pain/worry. Trust your instincts with regards to mechanics and do your research on their reviews etc xx

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Is there anyone on here near Bristol that could recommend a good garage?

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1 hour ago, Nazzywazzy said:

I think my next step is to take it to someone for a proper diagnostics rather than relying on the vagcom 😫

I hate to say it, but diagnostics are as good as the software INSIDE THE ECU... When you design an ECU, certain things have to assumed to be ok, so diagnosis can be hit and miss. That's where the autoelectricians earn their money. It's more thinking, head scratching and relying on past knowledge than actual "doing" usually. Electrics are like christmas trees lights- it takes just one in the chain to knock them out. Then it takes time to find it.

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2 hours ago, loopydebs said:

Is there anyone on here near Bristol that could recommend a good garage?

I liked the guys near Eldon road.

They were sound and kept lending me stuff.

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