V70 idling and surging problems.
 

So, can anyone help ? 2001 Volvo V70 T5. Fault codes as in image, but main one is 644a. This can up last year and I bought a new camshaft reset valve and fitted it. It does not seem to have fixed my rough idle or the surging at low revs. Also had pcv system replaced, new oil trap etc, and that doesn't seem to have helped. Can't find any obvious vacuum leaks, but getting smoke test next week. A few fault codes are about the etm and I wonder if a faulty etm can throw up other codes ? The etm is a marelli yellow label. Anyone got any clues as to what I can do, without taking it to the local stealership ? Thank you.

Take the etm off and clean off all the gunk around the butterfly. After that I’m not sure.

Get specific step by step advice on the TB cleaning before starting because from what I've heard there are a number of pitfalls and it's an expensive item

Hi.
Throttle Pedal Position Sensor is U/S..
Throttle body , Throttle pedal and Engine Control Module are interlinked.
The Control Module doesn`t know where the pedal position is so is constantly adjusting.

Hi. You need to check the engine timing.
The camshaft belt may have been changed but the the timing wasn`t done properly. If it `s not done right the timing marks may appear correct but the camshaft can be out of position . You need to check at the opposite end of the engine where the camshaft lock tool is fitted.
Clean the Throttle body as the other post suggests. If all else doesn`t fix it then look at changing the unit.
You say you`ve changed the "re-set unit" . Do you mean the VVT Valve ? If so,
is the gasket leaking ?

Amongst the more important checks would be to
a) check that the silicon vacuum/air lines are attached to the filter box and that all "rubber" connectors on those silicone pipes are intact
b) change the air filter
c) change the plugs
d) change the fuel filter
e) carry out a plug coil pack check, ie switch no1 coil pack to number 2 (replace 1 with 2) - note any change, then swap no3 to no4 (replace 3 with 4) then swap no5 to no1 (replace 1 with 5)
note any change, then swap no5 to no 1 (replace no5 with no1)
f) clean the air flow meter/sensor with AFM cleaner eg Liqui Moly 4066 Air Flow Sensor Cleaner- DO NOT USE ALCOHOL

Similar problem here. I did clean my MAF sensor with alcohol. Did not soak it just brightened it up with a Q tip dipped in isopropyl. Did I trespass?
With car running if I disconnect MAF the car immediately dies which makes me think it's working. I had never seen this warning in fact I read on forums that alcohol was ok.

cheers, Caleb 2001 XC70 2.4
New Orleans

There are various warnings about using methyl or indeed ethyl alcohol; I've no idea what MAF the primary component of MAF cleaner is - all I do know is when I used methanol it didn't make any difference but using a dedicated MAF cleaner afterwards did the trick!

That's good info on the dedicated MAF cleaner. My experience so far is when I unplugged MAF initially the car ran the same as when it was connected. So I cleaned with alcohol and repeated test and the care stalled when removed.

So apparently alcohol has done the trick for me. Altho this does not mean it is functioning correctly, only that its doing SOMETHING now!

Does anyone know if the car "should" immediately die when MAF is unplugged ?

If so I think I'll leave it alone, cheers