ETM Cleaning and P0101 / P2188. VIDA ECM-120D ECM-121B ECM-216D ECM-21E0 SOLVED

[hoo8it]

Hi all, this is my first post please direct me to the correct place to post future write ups and information I am unsure I'm in the right thread to post.

I wanted to share my troubles for anyone who may need this information in the future.
2005 XC70 155k
I bought it last summer and it has been hell but it has gotten me much more involved in the car/Volvo community and these forums (I only changed my own oil once before I owned this car)

The issue at hand started around mid Nov when it started to get colder here in GA after work she started and stumbled a bit 15-30 sec but eventually leveled idle rpm and all was well on the way home the CEL came on. AutoZone's scan told me I had code:

P0101- Mass or Volume Air Flow Circuit Range/Performance
I cleaned the MAF and my CEL went away for a day then came back on
I cleaned the MAF once again and my CEL did not come back for maybe half a month

Issues were especially relevant on start up but mostly noticeable at lights when id stop, intermittently the car would stumble at idle but it never stalled on me while I was driving (though it did twice both immediately after start up both times cranked after that w stumble)
with leaving overnight and starting in the morning the issue was common
it would skip the high rpm warm up cycle and I knew it would stumble
if held rpm around 1500 or so in park after start up sometimes it would kick in the warm up cycle and slowly drop to idle
sometimes would hold rpm at idle/light bc scared to stall
I found that if I primed it in key position 2 for 30 sec and listened until the electric humming went off then started it would be less frequent (i think this is because it would do a small etm calibration causing it to not get stuck?)

A month or so later of living with this issue, as it is my daily, I'm broke, and doing the repairs/learning them at the same time, I finally got a DICE unit and VIDA it read codes:

VIDA:
ECM-120D Air Mass - Signal too low
ECM-121B Mass air flow (MAF) sensor - Flow too low
ECM-216D Long-term fuel trim, bank 1 - Signal too low
ECM-21E0 Long-term fuel trim, bank1 - Faulty signal
Cleared them and they kept coming back (quickest to come back were the first two) but they were all intermittent

Possible causes from research I had done in all of our volvo forums (thank you) possible issues were:
Bad MAF
Bad O2 sensor (front more likely than rear)
Dirty Throttle Body
Bad Fuel Pressure Sensor/Pump/Filter

First plan of action was to acquire a new MAF, I am not paying dealer prices. I went to Pull Apart Atlanta east and got me a new MAF 35 bucks not same year or model (from S60) but housing and actual MAF were similar if not the same. I replaced the MAF with the new one and she ran perfect for a day and like 80 miles no stumbling at idle or anything.
Then it came back.
As my MAF attempt did not work and I had heard on these forums that many times the MAFs actually do not fail I figured I did not just have 2 bad MAF.
My PCV parts were coming in soon so I waited until those arrived to clean the throttle body with the manifold off hoping that would solve my issue.

ETM
CLeaned the ETM (throttle body) very well with carb cleaner it was moderately dirty probably just enough to not let air flow in the small slit openings while butterfly is fully closed (did not take a before picture, forgot sorry)
https://i.imgur.com/zuE6z7z.jpg?1

Now clean
When I moved the throttle body side to side I could feel something rattling slightly in there side to side so I decided to take off the electronic/gear cover as well this video helped immensely in this task
2004 Volvo V70R Throttle Body Removal and Cleaning

I found the first gear larger white one was loose on its pin, so loose that when i flipped it with the cover off the gear fell on to the floor straight off the pin i reinstalled and put a rubber washer on the pin to maybe keep the gear stable i closed and operated the butterfly but it had extra resistance so i took the rubber washer back off and this time the gear was not loose like it had been clamped in place by the extra thickness of the rubber washer pressed to the housing
https://i.imgur.com/6Ald541.jpg?1

Reinstalled ETM onto intake manifold after PCV Service (had to install while manifold was in car as to thread pcv banjo bolt (PITA))
used OEM ETM gasket
https://i.imgur.com/sMXy827.jpg?1
Could not get gasket mating surface completely clean without scraping metal on metal decided to install like this above best i could get it

so far I have had no issues all my lights / stumbling problems have gone and not resurfaced as im hoping they wont and ive put a hundred or so miles on the car

So my advice is if you have similar issues/symptoms give the throttle body a clean just to see if it helps, if not well now your throttle body is clean. I dont believe my pcv service was the problem/fix as most of it was free of major debri and not clogged.

Thanks for reading, I have more information to give but since it's my first post not sure where to put it all so far ive done

PCV, all seats replaced from 07 xc70, rear exhaust cam seal, oil filter and change, fixed moon roof leak, trans drain and fill, "upgraded" charge air pipe, replaced headlight/fuel door module, fixed fuel door lock, swapped CCM (climate module just to test), IPD silicone TCV hoses, filler cap O ring, replaced PTC and intake to turbo hose, dipstick, IPD Trans torque mount, IPD upper engine mount, IPD subframe inserts, and miscellaneous outer lights (license plate, marker lights).​
I try to take notes and pictures of install and removal. I don't know if any of this information is needed to gunk up the threads that already have it in there.
Also I posted here because volvoxc forum does not get much traction, any point in posting there?

[goldxc70]

Old thread I know, but here's my two cents:
You can use pretty much any scantool to check the MAF sensor on your car. There are YouTubes describing in detail. I had a bad MAF in a 2004 XC70 and the problems associated with it all went away as soon as I replaced it with a new Bosch (OEM) MAP from RockAuto. Other good sources are IPD and FCP. Cleaning the ETM is always a good idea but won't help if your MAF is good. Think about it: if your ECM is getting erroneous information from a bad MAF, nothing downstream is not going to fix that.