Hi all. My 2005 S60R MT (90,000 miles) is having hesitation problems. It seems more likely when cold, but happens when warm sometimes as well. It seems to happen on acceleration mostly, where the power seems to just "drop out" momentarily. Badly enough at times that I feared the car would stall out (although never did.) Twice, it resulted in a check engine light, although it cleared some hours/day later. It's happening with increasing frequency -- probably now over the past three weeks.

I've faithfully done all the services (in fact, just put in my third set of plugs -- doing them each 30k instead of recommended 60k), plus all regular, on time, oil changes and various engine filters.

I understand that two likely causes are Turbo Control Valve, and Mass Air Sensor -- or perhaps simply the vacuum hoses (which don't seem to be bad.) Is it possible, from this description, to help me diagnose this? Is it also true that, for the dealership to get any useful info out of the "codes" the service light must still be on? And even so, is it also true that the "codes" aren't really helpful for this problem (something I read on the Internet)? Thanks --Don

 

This could be caused by either or both but take the car to a AutoZone or a like store and have them read the codes They do it for Free. They will be generic codes but they will give a place to start. The DTC are stored until the problem is fixed Most times and if this has happened more that once i would guess is that they are there. Find out what they are and post them.If non are present then The dealer is the only way to see what codes have been tripped . The Cel does not have to be on.Volvo can see what if any codes have come up in the past.

 

Thank you, MYS6T. GREAT suggestion. I used to work in sales at the dealership. They will work with me a bit, but it is still a profit center, and I'm on a limited budget. So, anything that gives me a good indication of direction to go is a good thing.

Do you think it's worth buying one of the code readers for my own future reference? Or are they on par with anything that AutoZone might do?

 

They are on Par with what AZ has but i myself bought one just because it is always easier to have the ability to do it myself. It is also a good idea to clear the codes then drive the car and see if any come back . Volvo's are some times strange with what they will throw as codes and then it never returns. Gl and keep us posted on how things are going. You can also try cleaning the MAF with cleaner. Only use Maf cleaner made by CRC. Autozone sells it. Remove the MAF from the car do not do it while its still in the car. The stuff is very Flammable . Give it a good spray down from both side of the sensor. Then spray the conections. Let it dry 5 mins or so reinstall it and see if that helps.

 

The codes reading I got today from AutoZone (great service) was "Fuel Rail Pressure Sensor" and then something "high circuit A" (I was reading over her shoulder.) This implies then, the "Fuel Pressure Sensor", does it not? Any likelihood of ambiguity here? Or am I relatively safe to go ahead and order/install this part? And, if this has been failing for some time, might this also contribute to decreasing gas mileage. Thanks to all who posted here!

 

What were the codes ?? P---- ??

 

I should have insisted to look at the number. Unfortunately, all she would give me is the verbal "Fuel Rail Pressure Sensor" which is P0190-0194. Looking over her shoulder at the what I saw on the screen, I would suspect that it's P0193 as it said something about "High Circuit.."

Thanks! --Sorry I didn't get the number. Should have insisted.

 

My S40 T5 had this exact same issue. It was the fuel pressure sensor. If you haven't gotten it replaced, I highly recommend it.

 

Thank you, JG. I did go on to replace that Fuel Pressure Sensor, and it did indeed fix the problem. I have more power than I've had in months, and it looks like this was the cause of decreasing gas mileage. --My current tank looks to be about 10% higher. (Did you find an increased mileage as well?)

For those who may view this at a time in the future, the diagnosis and installation (self done) were relatively easy: I went to AutoZone/Advance who put an OBDC meter on the port, and came back with "Fuel Rail Pressure Sensor" error code. Then something, I believe, about "Circuit High Input".

It was interesting. I have friends (former co-workers) at Volvo Service, and called to ask about this, who told me "you can't rely on their code reader", and to "bring it in." Well you know something? The cost of that diagnostic would have been close to the cost of the part; so I simply bought the part and put it in.

Now, secondarily interesting is the reality (that you can find on a web search) that The LAND ROVER fuel pressure sensor is an alternative part that will work in the Volvo application. Part says "Volvo" right on it. --And, for about half price. I was about to go this route when my job went sideways, and I had to get parts from Volvo right away: I had broken the PCV tube, and Volvo had the part, and I had the whole thing opened up at that point. So I simply went Volvo. But, if I needed another one tomorrow, I would choose the LR part.

The part's not too hard to replace for the DIY'er: remove the plastic cover over the fuel rail, BLEED THE PRESSURE OUT from a valve on the opposite side before doing anything else, then take a torx screw and one screw has it out. --And all back in.

Thanks all, for the replies.