I know I'm going to have to have the OBD-II read at an auto shop, but I was wondering what some common causes are for the check engine light on these. I'm new to Volvos.

I purchased the 850 from a guy who was a Volvo enthusiast and had taken really good care of the car; the only issues he was aware of was a very minor oil drip (something I have yet to observe) and the automatic antenna was broken (won't retract when the car is turned off). Other small quirks were cosmetic things— couple of chips in the windshield, and rust on the alloy wheels because the car had originally come from his in-laws in Michigan.

The car has 134k miles on it, but runs like a gem. It had an oil change done last month and he also had the heater core replaced the week before I bought the car from him. I test drove it prior to purchasing and it drove like a gem; totally smooth, no funny noises, nothing, and has continued to drive flawlessly. In fact, I haven't noticed anything odd about the car at all aside from the heater making short squeaking noises every once in awhile (mostly when running it high)— that is, aside from the check engine light. The check engine light came on the day after I bought the car, while I was driving on the freeway, and hasn't shut off since. We've had unusually cold weather here (well below freezing), for what that's worth, not sure if that could affect anything.

Anyway, I'm planning on taking it to an AutoZone when I get paid next and having them run a report on the OBD-II to see exactly what's up, but I was curious as to what the most common causes of this are in an 850. Like I said, the car starts up and runs like a gem. The check engine light is the only significantly odd thing about it.

 

Honestly, it could be any number of things. As for the squeaky noise, probably need to grease the blower motor

 

There's no single, common reason for a CEL. If it popped on while on the highway, it's likely emissions, and more specifically, the most likely culprit is the EGR valve in some way, whether it's flow or electrical. I have and EGR code that pops on the same way, but I have a 95 so I just go under the hood and clear mine out myself. Just get it scanned and if you have any questions the don't hesitate to ask. On a related side note, most auto parts stores scan your car for free. I should know seeing as I work at one. Just get the problem narrowed down and go from there. Best way to start.

 

Every car will be different. On mine, I get the Check Engine Light whenever I am doing stop start driving and it is always 1-4-3 - knock sensor code intermittent. Even changing the knock sensor and checking all the wiring hasn't helped. And it is totally random when it decides to come on too.

 

 

 

 

 

I don't think Scott's car has EGR. Should have the air pump.

Chrispy, you will likely need to take your manifold off to clean out the EGR ports in the valve & manifold. I usually clean those out real good when I replace the PCV. the manual recommends it every 100,000 miles.

Brick, are you pumping 91+ octane? That should cure/avoid having knock issues (that really needs to be repaired if you are using lower octane fuel).

 

 

91 octane is the lowest octane you can get here in Australia. I always run our premium 98 octane fuel.

 

Wow, thanks for all the info guys. I've see that guy's tutorials on YouTube before and am planning on using them. I'm not really sure which projects to pursue first with the car, as everything seems to be in good order aside from the CEL. I suppose I'll start with figuring out what the deal is there.

The previous owner did say he'd recommend a change in transmission fluid in about 5k miles or so on the car, and, like I said, oil's good until February. After the dud of a car that I had last, I'm really meticulous about keeping the Volvo in tip top shape, so these are all good things to know. I've heard changing the timing belt is important before on these, and the previous owner wasn't sure when it had last been done so I'm considering going for that regardless of whether or not it direly needs to be done. How difficult of a job is that? I've looked around online and have found places to order Volvo parts, it's just a matter of whether or not I can tackle that kind of job. How much does a timing belt replacement cost at a shop, on average for one of these?

 

The cost of a timing belt replacement depends on your location. Having a shop do it can range between $600 and $1200. If you can replace brakes, you should be able to do the timing belt. There are good tutorials and video's available to walk you through it step by step. If you know how to FOLLOW instructions, you can do it with the right tools.

I'm pretty sure that POST PURCHASE video puts things in priority. Timing belt and PCV are top of the list on these cars.

 

Thanks rspi for all the tips.

I just looked closely under the hood, and there's a "Conti" timing belt sticker on top of the plastic cover that says the timing belt was changed at 120k miles on March 14, 2012. The car is at 134k, so I presume the timing belt should be fine. They say to change it every 70k, I've been told.

Good to know it's been changed within the last year or so, I don't know if I have time to do a project like that at the moment, and I've stretched some funds buying the car in the first place (though it's been absolutely worth it)!

 

Checked signs to see if the PCV needs changed, and I'm pretty sure it does. A little bit of smoke does come out of the oil dipstick tube when the car is idling. Wondering if that is related to my CEL being on. Since I know the timing belt was replaced just over a year ago, I'm gonna prioritize the PCV as the first actual work I have done on the car. I'm gonna call around and get quotes on replacing the PCV, and maybe consider doing it myself— for people familiar with it, would replacing the PCV be a larger or smaller feat than the timing belt? Might order a PCV replacement set online here soon.