2004 XC90 Check Engine Light & Missing

Hustler · Post by **Hustler** » 04 Feb 2010, 19:28

2004 XC90 - T6
Just turned 90k

Only had it for a short time, ran fine up until this evening....

1st the check engine light flashed, pulled over to make sure everything was safe

Started the XC90 back up and Check Engine light stayed on

It stays on, but it flashes under acceleration at times

Checked codes w/ a scanner

It came up with P0300, P0301, P0305

(Random Misfire Condition, Misfire cylinder 1, Misfire cylinder 5)

My question is WHERE DO I START?

I thought of starting w/ plugs or coil packs, but what are the odds of more than 1 going out or mis-firing at the same time?

Post by **OEMVolvoParts** » 05 Feb 2010, 09:20

Well the flashing check engine light you see when accelerating is the car mis-firing under load/boost. That is not good. It's gonna need plugs and coils if I had to guess. Part number for the plugs is 8692072 and 30713416 for the coils ( you have 6 ). It's possible maybe a vac. leak could be causing some problems also. Since you just bought the car maybe you can get it inspected at the same time you get it diagnosed. Then you will have some idea of what to expect in the future.

To your last question it happens alot. These coils are not exactly the energizer bunny when it comes to longevity. If one goes, then the others are probably not far off and it will be difficult to narrow down which to change with a multiple mis-fire. Proabably going to need all 6.

Hustler · Post by **Hustler** » 05 Feb 2010, 14:12

Thanks for the reply

I checked for vacuum leaks and didn't find any (all vacuum hoses looked good, too)

Are there any coils that are better than the stock ones, or anything else that people recommend?

Is there a way to check each coil?

I saw that Bosch Platinum plugs are not recommended by most people, I have never been a fan of them anyway

Is there any other plug that is recommended, or should I just go get them from the dealer?

green27614 · Post by **green27614** » 05 Aug 2010, 09:09

you have two coil packs that are bad or two spark plugs that are bad.
check the spark plugs first- they are the cheapest replacement.
I replaced mine about 20K miles ago with new pulstar plugs. they are pricey about 25 a plug but they do make a diff in gas mileage and performance. If you go this route be sure to follow the instructions for gapping properly or the plugs will not function properly. they have a diff gap as compared to a standard plug. BTw, these will NOT void a warranty of any type. the manufacturer guarantees it.
When you remove the plugs inspect the ceramics for cracks and look at the remaining amount of electrode. This will tell you if the plugs are gone. if after you replace the plugs you still have the check engine light on, then you have two bad coil packs.
I went through this process myself after going to a shop and having a tech tell me my plugs were ok. When i removed the plugs and inspected them i was SHOCKED to see that 4 out of the 5 plugs electrodes were all but worn down to the ceramics.

PurpleFrog7419 · Post by **PurpleFrog7419** » 20 Dec 2016, 14:00

My check engine light I see flashing. It started last week, so I stopped driving it. It went to the mechanic's today, and got a full tune up, new sparks and all. Had a hose replaced, too, that was spewing oil. But the check engine light is still flashing when I'm load bearing. I had the coil changed last year. I do still need one of the O2 sensor warmers replaced. Could this be why the check engine light is flashing when load bearing?

Post by **precopster** » 20 Dec 2016, 14:28

Best to post in forum matching your vehicle however same applies to your car as above post from 2010.

There are 6 coil packs and replacing 6 of them would be expensive. Did the mechanic use Bosch OEM coil packs or a copy of them? Some brands have good longevity and some don't. Delphi brand sold on Amazon would be a good choice on a budget as Delphi produce coil packs for local USA manufacturers as OEM equipment. https://www.amazon.com/dp/B00CJFLRGA/re ... CXTOL1P5S2

Reading codes narrows down exactly which cylinder is misfiring. You may only need one coil pack.

Get a code read done at Autozone, Napa etc then act quickly as misfiring causes unburned fuel and possible catalytic converter damage with prolonged misfires. Post the codes read here and we'll get back to you.

Post by **gstallons** » 31 Dec 2016, 11:13

Get a set of spark plugs ( Volvo brand ) and install them . Use a small amount of anti-seize on the threads and dielectric grease in the plug boots .
This should take care of your misfire condition. Make sure you reconnect everything so you will not have to take it apart to see what you left undone .

Post by **oragex** » 31 Dec 2016, 12:41

PurpleFrog7419 wrote:My check engine light I see flashing. It started last week, so I stopped driving it. It went to the mechanic's today, and got a full tune up, new sparks and all. Had a hose replaced, too, that was spewing oil. But the check engine light is still flashing when I'm load bearing. I had the coil changed last year. I do still need one of the O2 sensor warmers replaced. Could this be why the check engine light is flashing when load bearing?

As above, you may have a cracked/failed spark plug. Not all, one it's enough. Does the engine shake as well? Severe misfire can also be caused by a faulty injector or damaged wiring (check grounds on top of the engine as well while there), I had the light flashing when one of the injectors was broken )again no need to change all of them, one injector from a scrap yard can be used to test).

Post by **gstallons** » 01 Jan 2017, 20:08

To Purple Frog...
You got a full tune-up. Explain what comes in this " full tune-up " .
You got a hose replaced . What hose did you get replaced ?
Your check engine light was / is on . What codes were found ?
The 02 heater is a part of the 02 sensor , if it is bad you replace the 02 sensor.