volvo s40 2002

sirjohns40 · Post by **sirjohns40** » 22 Aug 2011, 15:12

Please help. OBD read p0303. 3rd cylinder (From the timing belt) has ignition coil.. So does the 4th cylinder.
I swapped 3 and 4 cylinders and the car didnt start still but the light cleared. I could nt get 4th cylinder to give off code.
I swapped it back again and the car actually started.

My problem was the car wasnt starting and the OBD said p0303. Ive always had the car hesitate at 55mph to 60mph. I cleaned the MAF before but no change. I put new air filter too. But this was existing problem. not sure if anything to do with it.

If 3rd cylinder is misfiring what else should i do? Should I just buy new ignition coil for #3?

Post by **zulu-v40** » 23 Aug 2011, 20:13

Well sirjohns40, I feel ya. My v40 misfired twice today while leaving the parking lot at work. Unfortunately for me, there was no check engine light to shed light on things.

Like you wrote, P0303 is a misfire for the 3rd cylinder. You'll probably need to order a new engine coil pack. Just curious, what did the bad coil pack look like? Were there any cracks or irregularities?

While you're at it, you could replace the spark plugs and spark plug wire set. When were the plugs/wires last replaced? If you decide not to replace the plugs, at least make sure they are gapped properly. I've read that even one poorly gapped plug can cause problems.

FCP Groton has the engine coil pack you're looking for - $37.50
tinyurl.com/3d5wqaa

I think those are the easiest, cheapest things to troubleshoot first. It could also be a faulty oxygen sensor or fuel injector, both of which are more expensive to replace.

Post by **jimmy57** » 23 Aug 2011, 22:03

that is a wasted spark system. it fires two plugs at once. Coil sits on one plug and has a plug wire to the paired cylinder. 1 and 4 and 2 and 3 are the pairs. If a spark plug has a too wide gap of the pair then it only sparks the closer gap plug as the spark voltage builds and is discharges on the closer gap before it builds enough voltage for the wide gap. Basically I'm saying look at plugs before you do a coil. A bad coil on that system usually kills two cylinders.