Help Please Aygo Idle Air Control Circuit Fault

[ch_shabs]

hI everyone

i am a new owner of an aygo i recently bought thinking it would be a simple fix and be a cheap car for me but i am struggling to get it sorted so thought i should post it and see what the experts think.

The car once started wont idle normally and is just bouncing the revs up and down all the time. I have changed the throttle body 3 times but it is still the same. it keeps comin up with p0511 idle air control valve which should have been cured when changing the throttle body.

I thought maybe somebody has had the same problem and knew what it is.

any help is much appreciated as it is annoying me now just revving up and down everytime i stop at a giveway or lights etc lol

Thank you

[Devon Aygo]

P0511 Is related to the Idle Air control valve circuit but it does not specifically mean a faulty IAC, the diagnostic procedure requires that resistances across the wiring harness, Engine ECU terminals and throttle body electronics are checked and confirmed. The procedure also requires active tests to be carried out using diagnostic computers and only then subject to the combined findings does a part such as the throttle body or Engine ECU get replaced or a repair to the wiring harness get carried out.

After three throttle body's it is quite probable your issue lies elsewhere.

[ch_shabs]

P0511 Is related to the Idle Air control valve circuit but it does not specifically mean a faulty IAC, the diagnostic procedure requires that resistances across the wiring harness, Engine ECU terminals and throttle body electronics are checked and confirmed. The procedure also requires active tests to be carried out using diagnostic computers and only then subject to the combined findings does a part such as the throttle body or Engine ECU get replaced or a repair to the wiring harness get carried out.

After three throttle body's it is quite probable your issue lies elsewhere.

hi thank you for your reply

I am pretty sure the problem lies elsewhere too but was eliminating that straight away. I have worked out why it is doing it as I opened the idle air control valve to check it and it was all the way in.. I pulled it back out fully and put it back in the throttle body started the car and it was idling as it should.

the only thing is everytime I click the ignition on the valve is slowly going in but doesnt come back out so then it starts bouncing the revs when it gets stuck

im not sure why it is doing this so thought the next fault could be with the wiring but couldnt see anything wrong with it

so what was left.. I got a second hand ecu set today started the car and it was still doing it!!

Now im really stuck :(

Im now thinking of changing the full loom what do you think?

Appreciate your reply

thanks

[Devon Aygo]

Honestly before buying and fitting more parts pay for some Toyota diagnostics

[Mantas17]

Did you manage to sort it out? I have the same problem with mine, just wondered where should I start...

 

[AYGOMAN07]

Iv got the same problem, I was also going to change the ECU but after reading this, I'm thinking it could be the Map sensor or intake air temp sensor? any suggestions would be greatly appreciated as I dont have the money to go to main dealer.

[ch_shabs]

Hi if it is bringing up the throttle body fault and you have changed it but had no joy then take a look at the loom goin to the throttle body. 

One of the wires to the throttle body had a break on it in my car so was bouncing the revs up and down. I put a multimeter on It to check and then stared to strip the cover off the wires and found a broken wire straight away close to the throttle body connector area.

 

Hope this helps 

[AYGOMAN07]

9 minutes ago, ch_shabs said:

Hi if it is bringing up the throttle body fault and you have changed it but had no joy then take a look at the loom goin to the throttle body. 

One of the wires to the throttle body had a break on it in my car so was bouncing the revs up and down. I put a multimeter on It to check and then stared to strip the cover off the wires and found a broken wire straight away close to the throttle body connector area.

 

Hope this helps 

Thanks Ch I'll give that a go too

 

Much appreciated. 

[AYGOMAN07]

On 2/22/2018 at 9:59 PM, AYGOMAN07 said:

Thanks Ch I'll give that a go too

 

Much appreciated. 

Just an Update my car had the exact same symptoms as described in this thread and it turned out to be the blue wire from ICV wiring loom. Car is running great now. not bad for 1 litre that has covered over 171000 miles :)

[liltoyota]

I am also having the same problem the IACV goes back in so it sucks to much air in the top part of throttle body (see pic) what does this valve do or need to do ?

Why does it close and not stay open if i wedge it to the open postion it idles as it should for a while but slowly goes back in...

What would happen if i permantly made the valve stay in the out position? Maybe wedge something into spring pic2

By the way i bought another throttle body from a breakers for £10 that the engine was idling fine

[liltoyota]

Its was Green wire snapped problem solved read a lot about these wires normally green or red

pic below