Mk4 ecu problems

**Bish** · 24-02-2018, 07:24 PM

So I have a misfire on my mk4 03 gti 160000kms. I scanned it and a coolant temp sensor came up as well as throttle valve so I did the coolant sensor which didn't fix it. So next I replaced the plugs, that didn't fix it. So went to the next, did the coil pack on cylinder 1 and that didn't fix it either. My ignition amp is fine I checked it with a multimeter and the wiring to the coil packs is also sweet as per multimeter readings. Thought I'd get it scanned with a mechanic I know and this time injector 1 and 2 came up. First thing I did was check the electrical pulse to the injectors and it was all good so I did the cheap option and used Liqui Molly injector cleaner for a couple of tanks and that didn't fix the issue. When I was overseas someone kind enough to my car to their mechanic and he did a run through on the same checks as I did also checking and cleaning my injectors. The mis still didn't get fixed. He had suspicions that it was a computer fault and so sent it off to someone else to check out the computer. Iv been back from overseas for 2 weeks now and they still can't fix it. Next resort is to change the ECU. Now Iv got a couple of options.

1) go genuine which will set me back big $$$
2) go used/upgraded to a stage 1

I'm leaning to going used but I don't know what I'll have to do to get a used one to work properly on my car.

What are your suggestions? Anyone have similar issues? Any other suggestions?

**h100vw** · 25-02-2018, 11:41 AM

06A906018CH is going to be the part number.

You can swap the immo chips between old and new ECU and that should work

**Bish** · 25-02-2018, 12:07 PM

Ok sweet. What are the advantages of buying a new one as opposed to used

**h100vw** · 25-02-2018, 12:10 PM

I wonder if you can actually get a new one. Your wallet will appreciate the secondhand one more.

**Bish** · 25-02-2018, 04:52 PM

Does that mean I can go and rip one out the same car at the wreckers?

**Umai Naa!!** · 25-02-2018, 06:26 PM

New one will be an exchange refurbished unit.

I think by 'new' he means new to the vehicle, not brand new.

**h100vw** · 27-02-2018, 07:23 AM

the immobiliser wont work on anything that you just fit to the car.

You could get one from a wrecker though. It would start for a second and then cut out.

**Lynchy** · 27-02-2018, 06:12 PM

Just from my research and for my 2c, If you managed to pull the ecu, instrument cluster, barrel and key from a wrecked car, you could do the swap without needed to defeat the immobiliser.

**beale187** · 27-02-2018, 07:16 PM

Originally Posted by Lynchy

Just from my research and for my 2c, If you managed to pull the ecu, instrument cluster, barrel and key from a wrecked car, you could do the swap without needed to defeat the immobiliser.

Ooh good question. I know where your going with this Lynch. In your case (and mine shortly) im thinking the BCM (body control module) would be different? Maybe someone more enlightened can answer this...