2002 2.0 will not start - no spark

[steveclv]

After much help and diagnosis, the Beetle still won't start. Been thru the fuel system and diagnosed that it is something electrical as there is no spark.

Checked all the relays, fuses etc and I have discovered that the ignition coil is loose - the retaining bolts were out about 1". Does the coil use the block as a heat sink? Could it being loose have caused it to fail completely?

As I browsed eBay for a possible replacement I came across someone selling replacement ignition keys for a 2002 Beetle with a transponder - did the 2002 have an antitheft system that uses a transponder?
Could my transponder have failed allowing the engine to be spun on the starter but just not start?

I only have one key so can't try another without getting one programed and of course it's going to be hard to get it to a dealer to have it reprogrammed LOL.

So any thoughts on the loose coil and whether the 02 had a transponder ignition?

Many many thanks!

[steveclv]

Does anyone have a diagram of the relay id 109 which appears to be something to do with the ignition system?

I found a pdf of diagnosing the 1.8T but didn't have much on the 2.0L so if anyone has a step by step diagnostic list that would be great.

[walnut]

Don't know whether the loose mounting bolts would cause failure, but my '02 definitely has the transponder key and immobilizer. But if i remember correctly, in the case of a problem with the transponder, the car will start, then immediately shut off.

[Skoobahead]

I found my coil loose when I purchased my 2002 used also. How this happened is beyond me. The coil does fail especially on a 10 year old car. Mine failed last year. Replace it along with plugs and wires. I doubt its your ignition key.

[MyOtherRidesAVette]

Originally Posted by steveclv

Does anyone have a diagram of the relay id 109 which appears to be something to do with the ignition system?

I found a pdf of diagnosing the 1.8T but didn't have much on the 2.0L so if anyone has a step by step diagnostic list that would be great.

I'm working with another Orger in another thread with a similar problem, and having to go through a bunch of diagrams. I'll find your relay circuit, and help out here too. I'm showing 109 as being in Position 12 on the main panel relay, indicated "power supply (terminal 30b, B+) relay"

Walnut is correct, with the Immobilizer III system, which is used in your vehicle, the car will start, but then shut down, it will not prevent it from starting.

I'm not showing Relay 109 anywhere in the 2.0L Motronic Engine Management circuitry at all. I have put up at the bottom of this post, the applicable sheets from the '02, 2.0L engine wiring diagrams related to the coil.

You say "no spark" but you don't say if you have voltage at the coil. That would be the first thing to check. If not look back at the ECM power supply relay [J271] in the protective housing, in the engine compartment (see attachment, last page). If the coil is getting voltage, coils can be bench tested. It could be the coil or it could be a bad ECM [J220] or the respective wiring or connections between it and the coil.

You can go here to get a printable .pdf "Understanding Bentley Wiring Diagrams"
http://newbeetle.org/forums/attachme...1&d=1316943580

Hope this helps! Best if you p/m me if you need something as I don't see all follow-up posts and don't necessarily follow-up on my posts.

MORAV

[steveclv]

Thank you all!

I had no idea about the ECM power relay under the hood so will check this first and then will bench test the coil and get back to you.
I don't think I have ever worked on a car that is so confusing with cause/symptom effects.

[MyOtherRidesAVette]

Originally Posted by steveclv

I had no idea about the ECM power relay under the hood so will check this first and then will bench test the coil and get back to you.

As I said check for 12V power at the coil first. If it has power the relay is more than likely okay. If not, move on to the relay.

Originally Posted by steveclv

I don't think I have ever worked on a car that is so confusing with cause/symptom effects.

, Gotta' it!

Btw, p/m rec'd and p/m replied to.

[steveclv]

Sorry for the late rely

After much searching and testing we found that we had fried the engine computer after the battery was changed over

Put a new used computer in and it fired right up but then died. Standard security system I believe.

Is there a way to bypass the security system or do we have to trailer it to a main dealer (280 mile round trip) to get the new used computer coded to the car?

[D2Beetle]

If you can find someone with VCDS (Vag-Com) they might be able to do it.