# 2003 Jetta 2.0L Coil Pack Resistance Measurement Help Needed. Please!



## steveo42 (Dec 30, 2007)

2003 Jetta 2.0L starts up and idles horribly, driving it the car has no power with the pedal to the metal it does 15mph. It's throwing codes P0300, P0302 and P0303 so I am suspecting the coil pack. The car recently lost the coolant pipe and coolant was everywhere in the engine compartment.
Also the MIL light is flashing.
I removed the coil pack and can see very fine cracks in the case which kind of confirms my suspician.
My question is, from what I can gather, I should be getting about 4kOhms or so between the 1+4 and 2+3 towers on the coil pack.
Is this with the pack INSTALLED IN THE CAR, or out on the bench?
On the bench, I get 0 ohms between the top and bottom (1+4?) towers and 15. Megaohms (steadily rising) between the 2 middle towers.
Again this is off the car.
It appears that the bolts also ground the pack to the engine block from what I can tell so that might effect the resistance measurement.
Can someone confirm all this before I waste $200.00 on a coil pack.
I've searched and searched and most of the hits I get are for the 1.8 and V6 or the other style coil pack with the towers on all four corners instead of in a line.
TIA so much for any help!









_Modified by steveo42 at 6:28 PM 11-16-2008_

_Modified by steveo42 at 6:34 PM 11-16-2008_


_Modified by steveo42 at 7:12 PM 11-16-2008_


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## steveo42 (Dec 30, 2007)

Bump!
Anyone?


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## steveo42 (Dec 30, 2007)

Well I answered part of my own question. Resistance reading is the same with the pack in the car or on the bench. 1 and 4 are open, sometimes very high values in the megaohms. 2 and 3 are about 4.5 MegaOhms, not kOhms. I ordered a pack, plugs and wires along with a Bentley manual seeing as I have 2 of these pigs and seem to spend more time working on them than I would like. They belong to my daughter's BTW.
I bought a Mustang GT vert and every time another part on the Jetta's break, I am reminded of why I didn't buy a GTI instead of the Mustang.


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## steveo42 (Dec 30, 2007)

Just to add to the post so maybe I can help some other poor soul, I cleaned the mounts on the coil pack of deposits, cleaned the stanchions where it mounts on the engine block, plugged the wires etc back in and the car idles like a champ. Then I sprayed some water on the pack and the car was misfiring like crazy so the hairline, and I mean real hard to see, cracks are causing the problem.
However, even with the car idling perfectly, measuring resistance between 1+4 and 2+3 does NOT produce the 4k or so ohms it should. I am using a Fluke and double checked with another Fluke (I'm an EE) so something is strange here.
I can't wait to measure the new coil pack to see what it measures .


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## mvmarcel12345 (Jul 14, 2007)

*Re: (steveo42)*

I had the same problem with the hair line cracks. I hope I get you in time though because you don't have to drop 200 dollars on a new pack.
Buy some J B weld (5 bucks) and paint the whole coil pack with it. It's high temp epoxy. It will fill the cracks and the coil pack will be like new. I did it and my pack works fine now for over 30,000 miles since.
Marcel


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## steveo42 (Dec 30, 2007)

*Re: (mvmarcel12345)*

Yep got it just in time! I was able to cancel the order. I'm going to JB Weld it but I'm still wondering why the resistance measurments do not match the specs in either the Bentley or Haynes (shudder!) manuals.
It should be 4- 6 kOhms and I am getting readings up in the mOhm range.
Car runs fine though.
Thank you for taking the time to reply!


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## steveo42 (Dec 30, 2007)

Just to close out the thread, they ended up shipping me the coilpack anyway but they are taking a return anyway. I measured the resistance between 1+4 and 2+3 and it is ZERO OHMS so the Bentley and Haynes are both incorrect. They do not show the pack with the towers in a row, but instead the one with the towers on 4 corners so something has obviously changed.
Anyway, I JB Welded the original pack, installed new NGK plugs (AutoLite crap in there from previous owner) and new wires.
Car now runs like a champ!


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## Jay-Bee (Sep 22, 2007)

*Re: (steveo42)*


_Quote, originally posted by *steveo42* »_They do not show the pack with the towers in a row, but instead the one with the towers on 4 corners so something has obviously changed.

Plug wire posts in a square = AEG engine
Posts in-line = All the other MK4 2.0s


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## steveo42 (Dec 30, 2007)

Thanks Jay-Bee Mine is an AVH and has them in a line.
Interesting how none of the documentation mentions that the resistance test does not seem to work for this coil pack. At least it's not documented anywhere I can find. Both Bentley and Haynes show the square pack and say resistance is 4-6k between 1+4 or 2+3.
This is not correct for the inline pack using the outside posts, 1+4 and inside posts, 2+3. They must have changed something other than the physical packaging.


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