Former VWDieselParts.com Forum

Hi everyone and thanks in advance for any help you may be able to offer for my problem. My 2000 Jetta has developed a no start problem recently. Here are the details:

It is a manual transmission car, standard trim, no power seats or fancy stereo.

Key in position 2, no glow plug light, and no CEL

My scan tool which has pulled OBD2 faults for me in the past will not establish communication now.

Engine will crank just fine, but of course no start.

Battery cable fuses are in good shape, no corrosion, none are burned through.

I just recently had to install a new ignition lock housing which came with a new ignition switch as part of the assembly. Everything worked just fine after the replacement so I do not suspect this as a problem, but it was the most recent thing that has been done to to car so I figure it is worth mentioning.

Not sure if the 2000 uses a programmed key fob but last year when my 06 required a new instrument cluster due to odb2 failure (it's a racket I think) my spare keys would no longer start the car. cranked but no start. Do not know what would cause a programming fault to occur and in your case this is probably not what's happening. All the doggone electronics crap is what drives me to keep my 82 Rabbit daily driver forever. Doubtful the 2006 will make it 32 years.

My key fobs do still lock and unlock the car. My continued research seems to suggest a main power relay (item #109?) or a chafed wire from that power relay to the ECM. Seems like it's a purple / white wire that I need to be looking for.

unfortunately I don't know much about the MK4 but I know there are some others here that do. Hopefully they can help. You should be able to test the relay or at least locate it and pull it out and reseat it. I had a problem with an ECU relay on my son's Corrado that was too much resistance in the contacts, >2 ohms, so when we pulled current through it the voltage dropped below the level where the ECU would fire the ignition circuit. That was tricky to find but the new relay did the trick. Similar problem with a Honda Accord main relay that would prevent the car from starting when it was hot (or cold? don't remember). Replaced it, problem solved.

Sounds to me like the immobilizer has gone off or partially gone off. I believe 2000 vw's had it. Just something that might be worth checking. Their's lot's Utube stuff on it if you just Google it.

Battery cable fuses are in good shape, no corrosion, none are burned through.
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