I have 2 codes that showed up on my reader for 2000 Volks Jetta 2.0:

P0303 and P1255

I know the list of potential problems but am unsure which code to address first. I would also like to know if both codes are related and can point to the area where I need to start. The check engine light is on and it's running running extremely rough with a strong smell (catalytic converter).

Should I be checking spark plugs first for code P0303 or start with addressing the Short to ground problem (p1255)

Any help is appreciated.

  • 1
    Welcome to the site. Did you first try clearing the codes to see if they came back? Commented Jan 30, 2017 at 23:05
  • Hi Paulster2, yes, the codes were cleared and did come back.
    – JSmith
    Commented Jan 30, 2017 at 23:15

1 Answer 1


The P0303 is often a broken coil pack; Change that, and do all the spark plugs at the same time. You may even find that the short to ground (P1255) disappears.

If you want to verify the coil pack first, swap the #3 coil pack (not the wire!) with another (say #1), and clear the codes. If it comes back with a P code indicating the other cylinder (e.g P0301 for #1 cylinder), it's definitely the coil pack.

A faulty coil pack will make the car run very rough, may damage the catalytic converter (if unburned fuel is getting to it), and will put the check engine light on (because the fault is emissions related). Fix that, and then worry about the P1255 if it's still there.

  • Thank you for your help. Unfortunately with being a 2000 volkswagen instead of the subsequent years (2001-), you can't swap coil packs. For my year the coil pack is one large piece. I was able to buy it for $70 and will attempt to install it.
    – JSmith
    Commented Mar 21, 2017 at 21:47

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