2005 S60 2.5T with 155k miles. This car has a history... Previous errors were Intake and Exhaust P0026 and 0027. The fuse #5 that feeds all those circuits blew twice in the last two years. ​​​​​​​Had engine flushes and oil changed. Then had Intake and Exhaust Solenoid replaced with cheap aftermarket parts (Ebay), then put back in the original, cleaned Intake and Exhaust VVT Solenoids. The related error codes went away.
Then rough idle got worse and had - due to P0101 (= ECM-120C and 120D) Air Mass Signal errors - the Mass Air Flow Sensor and the Turbo Intake Sensor replaced with quality parts.
Now, after driving few miles, switching engine off and restarting, CEL comes up with Engine Service Required message and error P0101. Engine runs rough in idle, misfires, stalls. This ONLY seems to happen at engine restart after a few miles.
The funny thing: Once the CEL is reset, idle is much smoother, but still not optimal, misfires stop till I drive another few miles and restart a few times.
Repair shop suggested to replace Solenoids with original parts (already ordered, waiting for them). I am frowning at that, but ok...

Any input appreciated.

 

are all 20 million air vaccum hoses in place? at least so that there is no leak. i plugged many of my vacuum nipples and that makes it run fine. most vac ports i found are near the throttle

 

Thanks, they already have been checked.

 

When was the PCV system last serviced? The solenoids for the VVT are fairly easy to clean by hand if you get new orings for them. You already ordered new ones so thats a moot point i guess.

 

I can't say. What strikes me with this CEL issue that I can drive for miles without an issue, but the CEL, error codes and misfires happen after engine restart. Does that indicate something with the PCV system?

 

An old PCV system can cause a lot of issues in the area of rough idle, stalling etc. Instead of getting excess oil where it needs to go, it ends up going into the intake and you car will burn it and also coat the intake pipes in excess oil. These are serviced every 100k miles/ 10 years whichever comes first. There are a few ways to check the health of your PCV system. You can take the intake pipe off the throttle body and check for excessive oil, a little is fine and expected. You can take off your oil fill cap while idling and perform the "glove test" or place your own hand over it to seal it, if theres a vacuum on your hand, that is good, if it is applying pressure, not good. The glove test is taking a latex type glove and putting it over your oil fill cap, and see if it deflates and gets sucked down or if it inflates. Some peoples engines will have a whistling during idle, if you pull out the dipstick and it stops, another indicator of a PCV service required.

Like the other user mentioned, could be a loose hose somewhere, intake leak, or something of that nature. Check the corrugated areas of the intake piping. These areas are prone to leaks and may become for prevalent once the car warms up.

Also, if your issue is the PCV system, that may be why your VVT solenoids are acting up.

 

Thanks, very helpful! I'll forward this to the mechanic.

 

also if the PCV's oil separator fails, oil vapors can wind up in the intake which can dirty up the MAF. Assuming the PCV needs servicing, the tech should inspect the intake air path for any oily deposits and consider cleaning the MAF with some MAF cleaner (not carb cleaner).

 

Better I ask the tech to check the PCV before replacing the Solenoids. Would what you are describing trigger specific error codes? And would this weird CEL and misfiring after restarting the engine be one symptom?
Thanks!

 

So I did the glove test and it didn't pull anything in (actually used some plastic bag). Went to the mechanic around the corner and he never heard of a glove test, wants to check the PCV valve when I get the new solenoids. At this point, I guess I rather look for someone who is more familiar with Volvos. Can the PCV system be cleaned or does it have to be replaced (and if yes, will aftermarket parts do)?

 

use Volvo parts for this. You will also need to replace the coolant fitting mentioned in this video that attaches to the intake via banjo bolt. it doesn’t say it’s for your vehicle but it’s better than paying hundreds of dollars to replace a hose it connects to because you can’t buy it separately. Very good read and video about the Volvo pcv system

https://blog.fcpeuro.com/volvo-s60-p...-and-diagnosis

 

Thanks!
I'm not doing things like that myself. Car will go to a 30 years Volvo specialist in the morning. I guess that'll be a $1000 repair, if not more.

 

And as always, make sure this is an issue before having this job done. I’m sure the Volvo guy will be able to diagnose it for you well

 

We'll see. He called and told me that the electronic throttle needs cleaning (?) $312, a vacuum hose of the evap(?) system needs replacing $190.
He frowned at the recently replaced MAF, because it's not original Volvo ("seen trouble with those, let's see how the car does with the other two parts replaced").
Well, he didn't mention anything about Solenoids. The ones I ordered from https://www.volvowholesaleoemparts.com/ are finally arriving tomorrow. Guess I'll return and bite the restocking fee bullet.

 

is he pulling the intake off to clean the throttle body? If you are unsure when the PCV was last serviced, IMO it would be a good time to replace the PCV box, hoses, & banjo bolt.

I personally cant see an easy way to remove the throttle body without removing the whole intake unless he is able to fish his extensions in there to get at the TB bolts. The $312 for cleaning is all labor.

 

He also replaced a vacuum hose assembly and purge valve. Car runs smooth so far. Will put some miles on it and have is Smog tested.

 

Follow-up: Car run smooth, but CEL came up again after 16 miles with P2177 code - Too little Fuel Off Idle (Lean). Volvo-guy said next step is replacing MAF sensor (which was done weeks ago, unfortunately with an aftermarket model).
He quoted $480 for a new one incl install, after my cringing he replaced it with a used one which lasted two miles. So we put the Aftermarket one back in and I ordered a new Original Bosh from Amazon for (drumbeats...) $107. I actually might swap that one myself.

Question: I am reading that an Oxygen sensor might play into the "Lean" condition, but I see upwards and downwards sensors. Which one would apply and who makes them?

Thanks!

 

100% swap that MAF sensor yourself if it's needed, just make sure you put it back in facing the correct way. The upstream O2 sensor is what monitors fuel trim, but I do not think that would be your problem as it usually is not the sensors. The sensors are just letting you know of your condition.

Fuel trim issues are not often easy to correct when the engines are getting more complicated. I would assume the mechanic checked fuel pressure, intake pressure compared to nominal, throttle body values etc.

 

Thanks, will do. He told me that it's usually the MAF, next in line would be O2 sensor.

 

Replaced the MAF myself with an original Bosch from Amazon for $107 and all is good. Even brought it to the Smog Test and passed.
Went to the corner repair shop that implanted the Aftermarket MAF for $195 (part) and asked for refund.

Thanks everybody in this awesome forum!