2006 S40 misiring issues (codes PO300&PO301)

EIU54 · Post by **EIU54** » 13 Aug 2015, 07:32

Hello. I purchased a 2006 Volvo S40 last week for my daughter. It has 147,000 miles with the 2.4i (non-turbo) engine. The seller told me it just started misfiring within the last two weeks. It idles rough and even stalls out after driving it for a while. After you get going above 10 mph it runs fine. Whenever you get around 50-60 mph it will flash the check engine light and the hazard dummy light. It also hesitates/misfires going up inclines. I "thought" it would be a relatively simple fix. I took it to my local Autozone and they printed out two codes (PO300 & PO301). I swapped ignition coil one for ignition coil two: no change. I put a new plug in cylinder one: no change. I then swapped injector one for injector two: no change. I noticed that whenever I take the oil filler cap off I feel and hear suction and the engine idle increases. I'm not sure what to do next. Any help or guidance would be greatly appreciated.

EIU54 · Post by **EIU54** » 15 Aug 2015, 20:37

O.K. Did a compression check. Cylinder 1- 5-8 lbs (did it 5 times), Cylinder 2- 130, Cylinder 3- 130, Cylinder 4- 120, Cylinder 5-145. Accidentally started up the engine and C1 shot up to almost 150. Immediately shut it off. Intake 1 suction is a lot less then intake 2 (I noticed) when doing a compression check. Please advise what you guys would do at this point. Thanks!!

Craigd2599 · Post by **Craigd2599** » 18 Aug 2015, 19:40

pull the dipstick...does smoke come out when the engine is running? The oil trap might not have ever been changed. On this model volvo it's very easy. I bought the kit from FCP Euro and was very impressed. It was a genuine Volvo kit and set me back about $200
The oil trap is the PCV system for Volvo. They need to be serviced about every 75000. I'm guessing it was never changed out

Craigd2599 · Post by **Craigd2599** » 18 Aug 2015, 19:43

it could also be a faulty cam-phase sprocket. That's the VVT system Volvo uses. If that fails, the valve timing will be off

EIU54 · Post by **EIU54** » 18 Aug 2015, 22:00

Thank you very much for the response!! No smoke out of the dipstick. Having it looked at by a mechanic with a fancy diagnostic machine tomorrow. He thinks he will be able to pinpoint or isolate the problem. I will mention to him about looking into a faulty cam-phase sprocket. I'm sorry I didn't see your responses sooner. I really appreciate any help. Just worried sick it's a burnt valve which will cost me a lot more than I need to spend. Hopefully something that doesn't require pulling the cylinder head. Regarding the oil trap issue, I called Volvo last week and registered my car with them. They said my particular model didn't fall under the extended warranty for that. They did, however, give me a discount voucher to be used for Volvo replacement parts for the oil trap. Who knows.

Post by **juice2288** » 21 Sep 2015, 20:43

I had the same error code and symptoms as you did, it was a bad ignition coil on cylinder number one (furthest to the left(passenger side)). At idle and while running, it was fine, but at initial acceleration or during sudden acceleration while running, it would run rough and lose power. I tested it by swapping the number one and number two ignition coils, drove it, and when roughness re-occurred, I scanned it again and the OBDII scanner gave me a P0302 instead. So I replaced the ignition coil myself. While I was there, I also replaced my spark plugs. It is a pretty easy job, took less than two hours to do and only because I really took my time. The ignition module was $85 from the Volvo dealer, and $52 for the five Denso Irridium spark plugs from NAPA. It is running great now, much better than before. There are some good write-ups and videos online ( . Good luck