Volvo V40 2003 will not idle?

[Strongo]

Hi

I have a problem with my Volvo V40 2003, and I hope you can help me.

The problem is that it will not idle. I've tried the following:

1. Examined for errors using OBD2. It reports no errors
2. Cleaned MAF sensor
3. Changed the air filter
4. Cleaned various sensor plugs
5. Cleaned idle valve, and now also tried with a new idling valve

It will still not idle. I can control the idle valve, by connecting an external power supply, directly on the idle valve. So I think it is the actual control of the valve that is wrong.
But what is it that controls the valve? Which sensor tells how much the valve opens?

Hope there is someone who can help

[Strongo]

Is there nobody who knows which sensors controls the idle valve?
I might add that when I pull the plug of the valve and put it on again, the idle briefly increases only to fall and then stalls.

[thebaldavenger]

Hey there,

I'm having a similar problme with my 2001 S40 (full specs after message)

This has been going on with my car for over a year and four garages later....I'm back to trying to fix it myself...so maybe we can work together and get to the bottom of this?

This is a long(ish) post - sorry

i'm reasonably sure that the Mark I S40 and V40 are pretty much the same so I would be confident that a solution for one would provide the solution for the other.

Here is a link for a complete wiring diagram I found (have fun with that ) :

http://www.volvowiringdiagrams.com/volv ... agrams.pdf

I, too, hvae suspected for a long itme that the Idle Air Control Valve (IAC) was misbehaving - often it felt like it was half asleep, and would take a moemnt or two to react - this resulted in the idle dropping all the way down to 200rpm..before either(1) stalling or (2) jumping up to 700/800 rpms and behaving normally.

Having said that, "feathering" down through the gears instead of clutch and brake...was always better...it felt like any *sudden* demand on the IAC would result in it being "difficult"...like it was sleeping and had been rudely awoken...

I also agree with your own reasoning that this may be an electrical problme - more than likely with the wiring loom itself.

So, I buoght a multi-meter and started testing the circuits myself - I found that all the garages I aproached tried to find ways to AVOID doing any testing etc with the electrics - more than likely becasue it is time-consuming and requires genuine diagnostic skills, rather than having a scantool tell you what's up.

I had knock sensors replaced, Crankshaft position sensor - TPS, IAC, MAF...new coils...etc, etc.etc...not one of these made any real difference - needless to say I got all my old sensors put back...there is no vacuum leak either.

Do you find that once you're moving, the car runs fine?

I think either VADIS or VIDA (don't think VIDA works with mk I s40s) has the info you'll need on the voltage/resistance etc. If you need any help, there's plenty of youtube videos which demonstrate how to "back probe" a connection (basically, I used a paper clip, unfolded...and shoved one end through the back of the plug so that it has passed the rubber seal and is touching the wire)

If you sure the sensor is OK - then just isolate each section of wire and test for resistance (someone please correct me if I'm wrong)...buta reading of 1 is what you'd be looking for, as that would indicate an overloaded circuit.

This isn't a bad tutorial : http://www.robotshop.com/media/files/pd ... -10338.pdf

Don't be disheartened by this manual - from what you posted, you already have the necessary skills and attitude - most of this manual is illustrations of component locations...jump to page 18 of the manual (page 94 in your PDF viewer) and you'll see one half of the total wiring diagram....look to the bottom right for a square component 7/50 - that's the IAC valve...that should get you started in the right place. My system is EMS 2000 - you might want to check for your own first.

I have long suspected a "short" somewhere in my loom that is repsonsible for my intermittent idling bother.

I also think that if ANYONE has messed with the Throttle Stop Screw or the Accelerator Cable Adjustment Screw...this could result in a dodgey idle...again just my theory....as if the butterfly valve on the throttle body is the wrong position, the Throttle Position Sensor will present incorrect readings, which the ECU will try to "autocorrect"...and the result will be that momentary "confusion" as the sensors all quickly collate the data....this is what I think is the idle dropping (like it's asleep) before suddently fixin' itself.

Sorry again for the long post. Would you mind telling me what else you've tried OR if you found a solution.

S40 2001 !.8 petrol B4184S2

[Strongo]

Hey there,

Good to hear that I am not the only one with that problem.
It would be great if we were able to find a solution to the problem together.
I have studied the wiring diagram, but it doesn’t tell me what sensors controls the idle. Do you have any idea about which sensors control the idling? It will make troubleshooting a lot easier if we know which sensors to look for. Is it the MAF, temp sensor, throttle sensor etc., or all combined??

My car react the same way, it feels like the IAC is half asleep. Sometimes it "wakes up" after a little while, and other times the car just stalls.

I have no problems with performing the necessary measurements, it would just be nice to know what sensors to measure.

Unfortunately I have not had time to look more in to the problem, so what I've tried, you can read the first post. You may be right about the throttle position sensor, I will have a look in to that.

Hope we can find the solution together :0)