Ok, car has been fine since I bought it in october. Today I was just setting off from work when I noticed the speedo had stopped working and miles were not counting up. Then at roundabout the car almost stalled, with an idle going down to almost zero then back up to around 800 then down again....... Further on down the road, the CEL came on, but car still revved to over 4500. Light went off again at under 25mph.

I had read about that on here and just thought it must be speed sensor, so when I got home I connected the black connectors to read the ecu fault codes expecting it to give 33 (for a faulty vss2), but it actually gives a fault code of 24, which is the Idle Control Valve.....

Now I also have a pug 306 gti-6 and this is quite common on one of these and can explain the erratic idle thing, so I can understand that (having replaced it twice on the pug, which is for sale if anyone interested? )

What i'm wondering is, (eventually cuts to the chase!), can a faulty VSS give a error code for the ICV, (read it on here somewhere), and why...... Should I just get a speed sensor? or if it is the ICV, why has my speedo stopped working?

Me baffled. Please help me ob1, your my only hope!

 

Yes it could, the ECU trys to control engine speed when 1. your foot is off the throttle and 2. road speed is zero, if you have foot off throttle, no road speed cos it's bust and say slowing down in a gear the ecu trys to bring the revs down, but it can't because your still moving in gear, ecu by this stage has fully closed the ICV to drop revs, then you plant your size 9 on the cluch and whack, revs fall to zero.

As for the error code i can only think the ecu flags 24 as it was not able to control idle properly.

Hope that helps.

Used to drive Gold GTI with clock disconnected, stalled every day!!

 

Ah I see, yep understand that. That just leaves why the ecu is just showing error code 24 and not 24 and 33.

That still baffles me.

Does anyone have pics of the speed sensor on an my98 (terzo). I have had a look behind the turbo and there is a big sensor type thing behind the lambda, in the gearbox, but it seems to only have two wires?