P0300, and related, is a common DTC (diagnostic trouble code) that appears on most Volvo cars at some point in their life, and many times more often than you expect. This code is relatively easy to diagnose and repair, and typically does not cost much and can be completed by even the most armature of mechanics.
Essentially, P0300 and related codes (more on that below) is/are an indication from your Volvo ECM (car’s brain or computer – official name: Engine Control Module) that there is a misfire present in one or more of your cylinders. It is not uncommon that the driver will notice physical characteristic changes in the responsiveness of the engine when P0300 code presents itself, but not always.
Shuttering is even more evident on Volvo cars equipped with a high performance Elevate tune, or other tunes available in the market. Tuned Volvos (especially turbo equipped models) are more likely to feel these symptoms since the tune increases turbo boost pressure from 7-8 psi factory, to as much as 15psi, and at that level, a failing spark plug or coil pack has a harder time igniting the air/fuel mixture in the combustion chamber.
Do not fear, below we will fully explain why this occurs, step by step on how to diagnose this, as well as how to easily fix this problem and get that pesky P0300 code to go away while getting your car back to peak performance.
What is DTC (Diagnostic Trouble Code) P0300 on a Volvo?
Simply put, P0300 is a DTC (diagnostic trouble code) which is logged by your Volvo’s ECM (car’s brain or computer), that then causes your check engine light to illuminate. In most cases DTC P0300 will not be the only code pulled from your code scanner/reader. Think of P0300 as a “parent” trouble code, which could also be accompanied by a “child” code which could include a single or multiple codes as follows: P0301, P0302, P0303, P0304, P0305, P0306, P0307 and P0308.
The P0300 simply indicates your Volvo has a misfire that was detected on one or more of your engine’s cylinders. The accompanying code will typically indicate which cylinder(s) triggered that code. In some cases, depending on the misfire detection capabilities of the car, P0300 may present itself alone, if the specific cylinder misfiring cannot be detected. The other specific cylinder codes are numbered in ascending order, and each one corresponds to a specific cylinder. For example P0301 would indicate misfire on cylinder 1. P0302 would indicate misfire on cylinder 2, and so on. For 5 cylinder Volvo models such as S40, C30, C70, V50, S60, V70, S80 and more, the highest numbered P0300 code you would see would be P0305, indicating cylinder 5 has a misfire. For 6 cylinder Volvo models such as the XC60, XC90, V70, S60, S80, V60 and other 6 cylinder models, the highest P0300 related DTC code you would see is P0306, and so on for the two V8 Volvo models, the V8 XC90 and V8 S80, which could deliver you a P0308.
What Causes P0300 in Volvo Cars?
First let’s define a misfire to better understand what is actually happening in your Volvo. To complete a combustion cycle in the cylinders of your car, several things need to happen. First, fuel needs to be injected into the cylinder, followed by an electronic signal being sent from your ECM (car’s brain or computer) through the wiring harness to your coil pack, resulting in the coil pack distributing energy into your spark plug, resulting in a spark, which would then ignite the fuel. This all happens in mere milliseconds, thousands of times a minute in each cylinder. A misfire is simply when this process is not happening as it should. This could be for various reasons that we explain in detail below, but at the core either spark or fuel is not present in the amount it should be to properly complete the cycle. Misfire meaning, the firing process was amiss.
Here are the multiple reasons why your Volvo would be giving you misfire code P0300, and related. However, in many cases it is simple to diagnose and simple and affordable to fix yourself. Common reasons you would have your car present a check engine light and your code scanner deliver P0300 would be as follows:
Spark Plugs: The spark plug is tasked with receiving an electrical signal from your car’s ignition coil pack. Later model Volvos use a system of “Coil-on-Plug” which eliminates spark plug wires by having an individual ignition coil per spark plug. Chevrolet LS engines have individual coil packs, but they use spark plug wires on each cylinder as opposed to older model cars that use a master distributor to send this signal down spark plug wires to spark plugs. When the spark plug receives the electrical signal from the coil pack it will convert that into a spark (tiny flame) that will ignite the air/fuel in the cylinder. Spark plugs can be the culprit of your P0300 codes if when the spark plug is older and at the end of its life. The plug losses the ability to deliver the proper spark to ignite the fuel. Spark plugs can also cause misfires when they are not properly gapped. Finally, spark plugs can fail when head gaskets have failed and foreign material is introduced into the combustion chamber, this could be coolant and/or oil. Luckily for the first two causes, new spark plugs will remedy the problem. Pro tip: Volvo engines are heavily reliant on their electrical systems and that includes spark plugs. Volvo OEM spark plugs are recommended in every, and all applications. They are specifically designed to meet the demands of your engine, and electrical system. You can always find Genuine Volvo Spark Plugs on Volvo’s Website Here.
Coil Packs: By far, the most common cause of P0300 is the actual ignition coil pack. Mounted (and grounded) directly to the head of the engine via the valve timing cover, the coil pack slips down over the spark plug and takes the electrical pulse sent by your ECM, and then delivers it directly to the spark plug. The work of an ignition coil is tremendous as it takes a 12 volt signal and amplifies it to over 40,000 volts in a split second to be able to arc electricity across the spark plug gap. As noted above, most Volvo cars since the late 1990s have individual coil packs for each cylinder. This allows for a more precise and direct delivery of the electrical current needed to fire off the spark plug. Coil packs on your Volvo car are expected to execute a tremendous amount of the workload of the ignition process, and over time will eventually wear down and fail. When these coil packs fail, they cannot deliver sufficient (little to none) energy to the spark plug. As a result, the spark plug does not fire correctly, the fuel does not burn, and you get P0300. This however, is extremely easy to diagnose and to fix, both explained in detail in their respective sections below.
Wire Harness & Grounds: Further up the ignition chain is the wire harness and the grounding wires that are responsible for delivering the current to your coil packs. On most Volvos you have 4 wires that come into the coil pack. This is a control signal, a ground to the engine, a 12v supply via a fuse under a relay, and in some models like the 2.4 5 cylinder, the fourth wire is a misfire signal reader, while the 2.4’s older and more aggressive and muscular T5 engine detects misfires by calculating deviations at the flywheel to register misfires. The Volvo P0300 codes can be simply triggered by loose wire connections, ground wires not fully secured, and even worn out or broken wires. Volvo models even as new as the P2 generations are showing wear and destruction of wiring looking and protective casings. All these issues will cause reduced (or no) electrical current/signals to your coil packs, resulting in P0300 codes on your Volvo.
Other less common reasons you would be get the P0300 codes could be as follows:
- Failing head gaskets can leak oil or coolant into the spark plug housing, which prevents proper firing of the spark plug. Like trying to light a match underwater.
- The ECM of your car is failing and thus the computer is not generating the proper signal down the wire harness to the coil pack resulting in spark failure.
- Failing fuel injector or fuel injector electrical unit failure.
- Damage to the internals of your head – bent valves.
These are way less common in the presence of a Volvo Code P0300, but still could cause that DTC to be present. These issues would warrant inspection and testing by a mechanic and, depending on the cause, could bring with them a hefty parts and repair bill. Below in troubleshooting, we will explain how to rule out the most common failures, and you’ll be able to determine if you may have one of these more advanced issues causing P0300.
Troubleshooting Volvo Code P0300.
Now that you understand the basics of what P0300 for Volvo cars is and what can cause it, let’s talk about how to determine what component is causing your check engine light to illuminate.
Initially, you need to identify the specific cylinder that is triggering the misfire code. As explained above, the code that comes with P0300 will identify which cylinder is culprit, or in some cases which multiple cylinders got you into the mess. Here is a quick recap:
P0300: Random/Multiple cylinder misfire detected
P0301: Misfire detected in cylinder 1
P0302: Misfire detected in cylinder 2
P0303: Misfire detected in cylinder 3
P0304: Misfire detected in cylinder 4
P0305: Misfire detected in cylinder 5
P0306: Misfire detected in cylinder 6
P0307: Misfire detected in cylinder 7
P0308: Misfire detected in cylinder 8
Based on which combination of codes above, you now know which cylinders you need to inspect. Volvo cylinders are numbered in order, starting from left to right. Standing in front of your car, facing towards the trunk, cylinder one will be the farthest on the left. The numbers will increase in order from left to right, so for 5-cylinder engines, cylinder 5 will be furthest to the right. On 6-Cylinder Volvo models, cylinder 6 will be furthest to the right. The less common Volvo V8 (4.4L B8444s), will have a similar layout by starting numbering on the left side on the vehicle and moving towards the right, however there are 2 banks (areas where cylinders group together). When standing in front of the car looking towards the trunk, you will see four cylinders left to right in the front of the engine, and four cylinders left to right on the back of the engine. The front row closest to you is numbered 1,3,5,7. The row of cylinders in the back of the engine are numbered 2,4,6,8, odds closest to the front of the car, evens closest to the trunk.
Now you know which cylinder(s) you are inspecting, you can start your P0300 diagnosis as follows:
Start by looking at the wire harness. Is it plugged in all the way, make sure the plug is seated completely and the clip snaps to lock it to the coil pack? You can also remove the clip from the coil pack and look inside and make sure you see the metal pins in the plastic harness. Are they straight, not bent, not broken? Are the wires coming out of the harness in good shape, not pinched, cut or wire insulation scraped or shredded off? Is the bolt holding the coil pack to the head tight and secure? This bolt is not only securing the coil pack, it is a ground bolt for the coil pack. Bent pins can be straightened out with pin pullers of tiny flat head screwdrivers. Exposed wires can be remedied with electrical wiring tape. Cut of pinched wires can be repaired by doing a new splice or solder on the damaged area. Loose coil bolts can be tightened. If you noticed any of these issues, fix them. You can clear the code, start the car and let it run and see if the code comes back. If it does not, then you have solved Volvo code P0300. If not, don’t worry. Let’s dig a bit deeper.
Pull The Coil Pack. Here you will pull the coil pack off to inspect the coil pack itself. Most Volvo coil packs are secured to the cylinder head with a single bolt (part number 982759, which is a M6X25 with an 8mm hex head. Start by disconnecting the wire harness then grab your ratchet and 8mm socket and take the bolt out. Grab the coil pack and pull up firmly. It is hard to visually identify a bad Volvo coil pack as most of the time it is the electrical components inside that fail, however, you can look down the tube of the coil pack for anything that doesn’t look right. This could be a ripped of torn rubber boot, or a coil spring inside the boot snapped or crimped. Those are not likely, but possible. Set the boot aside for now.
Pull The Spark Plug. Grab your spark plug socket, in most Volvo’s it will be the 5/8 size. Remove the spark plug and inspect it for damage or wear. The ignition tip should be one solid clean piece, free of excessive build up or corrosion. Regardless of what you see, set that spark plug side for now. Look down in housing where the spark plug was mounted. Do you see any liquids, do you see oil? Those are signs of a head gasket issue, and you can replace everything you pulled off, and take to a mechanic for further inspection of a potentially more serious issue. If it is clean, great job, lets sort this P0300 out.
Swap Parts With A Non-Misfiring Cylinder. Here you will repeat the above steps on another cylinder that was not giving you a code. Example, you had Volvo Code P0304. Go to cylinder 1, pull the coil pack and the spark plug, no major inspection required since that combination was working fine. Now install the spark plug and coil pack from cylinder 1 in the misfiring cylinder, and install the spark plug and coil pack from that one in cylinder 1 (or whichever you removed from). A straight trade, which will now let you know if the coil pack or spark plug is suspect, which 99% of the time is the cause of P0300 codes. Secure everything, clear your code and then start your car and let it run.
At this point one of two things will happen:
- The misfire will have moved to the cylinder you swapped parts with, great news, you have isolated the issue to two variables, the spark plug or the coil pack. From here, turn car off, and swap the coil packs from those two cylinders, but leave the spark plugs in place. Clear the P0300 codes, start the car and let it run. What cylinder did the code come back to? Now you know if the Volvo misfire code was linked to the spark plug, or the coil pack. If the misfire followed the coil pack move, your coil pack is trash, and if it stayed with the spark plug, time to check the gap and possibly time for new spark plugs. More about that below.
- There was no change in the misfire cylinder, meaning the spark plug and coil pack are good. This again is RARE, but would indicate possible issue with fuel delivery such as clogged injector, bad injector, bad injector wiring or similar and even damage to the internals of the head such as bent valves. In this case a mechanic can do pressure testing and flow testing on fuel delivery, or for more advanced at home mechanics, they may swap injectors and try to isolate the fuel delivery issue. Fuel lines are pressurized and messing around with these components is not recommended for a weekend warrior mechanic.
Solved: Let’s Fix Volvo Code P0300 For Good.
Based on what you found on your troubleshooting mission above, here are the solutions, quick, easy and affordable.
If you have a bad spark plug, check the “gap” or distance from the center electrode to the ground electrode. With a spark plug gapping tool, you can read what this gap should be. In some cases the gap is too large or too small, which can cause the misfire. Use our chart below to determine the proper factory gap for your vehicle. If the gap is fine, it may just be time for some new plugs. Keep in mind that since spark plugs are typically replaced together, if one failed, the others are right behind, so you might as well order a complete set. Remember, Volvo only, while parts stores have cheaper options, that may seem tempting because your buddy’s fully built Honda K-series only uses NGK, they are not built for the specific demands of Volvo!!! Order our plugs here on Volvo’s Parts Website, or from your local dealer.
For spark plug gap reference, the good Volvo owners over at ImportSauce.com have compiled a huge Volvo Spark Plug Gap chart, which includes the spark plug gap, part number, coil pack part number, engine codes and so much more. It currently covers all Volvo models from the early 1990s through even new VEA (Volvo Engine Architecture) models. They have a free download of the complete spreadsheet, as well as their common engine quick gap guide, which we have here. You can see the complete chart and sheet on their website here.
If you had a bad coil pack, there is nothing you can do to fix it, it is time for a new one. But again, like we talked about above, it is very likely that the remaining coil packs will start to fail in the same manner. We understand being on a budget as we have all been there, but if you can afford it, replacing all coil packs at once will save you time in the long run, and could keep you from getting stranded on the side of the road later. The most affordable option for replacement is not Volvo, but Elevate’s performance ignition coils that deliver more performance, and cost only about 60% of what Volvo factory coil packs cost. More about that below, but if you’re a “only Volvo parts” kind of person, we understand, but keep in mind Volvo trusted us so much with the Volvo name, we were commissioned by Volvo Cars, North America to build them TEN different concept cars to spread the Volvo name and following. You can see the full custom builds of those cars here. But you want “Volvo OEM” only, no problem, you can get those coil packs at your local dealer, or on their website here. But remember, like everyone else selling electrical components for vehicles, Volvo DOESN’T offer a warranty on electrical parts. However, Elevate warranties their ignition coil packs for 1 year, UNLIMITED MILEAGE!!!
However, if you want to save money, and install a performance ignition coil, check out the specs of our performance ignition coils, at 60% of the cost of Volvo factory ones below.
Pro Tip: It is not likely, but also not uncommon, that you will purchase a brand new coil pack and it will be faulty out of the box. So if you plug your new coil pack in, and a code P0300 or related is present, you probably were sold a dud coil pack. If you purchased from a local parts store or dealership, good luck trying to get a refund or swap it out. However, if you purchased from Elevate, a brand new replacement is only an email away.
The Best Setup for Your Volvo Ignition System.
If you are looking for a coil pack upgrade to boost performance, and increased mileage for your Volvo, then consider taking care of that P0300 code, while also taking advantage of what our coil packs offer over factory spec.
Our performance ignition coil packs are a direct replacement for the Volvo factory part, no modifications needed, simply pop it in, plug it in, bolt it down and done. Our coil packs are sold as individual units, so orders on single units are welcomed, but as mentioned above, it is best to replace all units at once for optimum performance. You can see all the performance benefits of our coil packs by clicking the part number for your vehicle below.
We have left nothing out with regards to research and development of our coil packs, and thus we offer a one year, unlimited mileage warranty. You will be hard pressed to find anyone else offer any kind of warranty on their coil packs, simply because ignition components are considered a “wearing” component.
Please also confirm your part number, as not likely, but there may be a variation in your vehicle where you may use a different coil pack part number.
Volvo Coil Pack Part Number: 30713417 & 8677837: 5 Cylinder Volvo Models Including: C30 (2007-2013), C70 (2006-2013), S40 (2004-2012), S60 (2004-2016), S80 (2003-2006), V50 (2004-2012), V60 (2014-2016), V70 (2001-2016), XC60 (2015-2016), XC70 (2016) and XC90 (2003-2007)
Volvo Coil Pack Part Number: 30713417 & 8677837: 6 Cylinder Volvo Models Including: S80 (1999-2006) and XC90 (2003-2006)
Volvo Coil Pack Part Number: 31312514: 4 Cylinder Volvo Models Including: S60 (2014-2024), S80 (2014-2016), S90 (2017-2024), V60 (2014-2024), V60CC (2017-2022), V90 (2017-2021), XC40 (2018-2022), XC60 (2014-2024), XC70 (2014-2016), XC90 (2016-2024) and Polestar 1.
Volvo Coil Pack Part Number: 30684245: 6 Cylinder Volvo Models Including: S60 (2011-2016), S80 (2007-2015), V60 (2014-2016), V70 (2008-2010), XC60 (2009-2016), XC70 (2008-2015), XC90 (2007-2014).