I need guidance with using VCDS / VAG-COM

[ABV-VR6 12]

I'm new to this and I'm wondering if someone with experience would explain a few things to me. Like all good Corrado owners, I ordered the scanner. I was under the impression that all you could get out of it is error codes? 

Am I correct to think it needs to be plugged without the engine running, just on accessories? Sorry newbie question! 

So all I'm getting is :

1) 17978 immobilizer, which is normal as it was deleted with the remap Stealth did to the ecu. 

2) 00513 (G28) no signal and according to ross-tech website that's normal on obd1 car. Plus the sensor is new and oem. 

Here's the reason of my question. The car is idling totally fine (small lump from 268) and all is acting/working fine. But the one thing I'm noticing is the idle might be a little high? 850/900. Yesterday I was reading old threads on the forum and many were suggesting plugging the VAG-COM to know if my throttle was sitting at 14 degrees at idle as a starting point. Then narrowing down to air leaks. So, me, I thought all you could get was error codes from it? How do you access the throttle body to get this measurement? Other things I can scan that I don't know about? 

Sorry, this might be so simple for some of you but I never used a scanner before... Cheers! 

[ABV-VR6 12]

Ok I found by searching more and also by accident... But under "engine" you go to measuring blocs, I entered 002, 003, 004 and with the 003 I got the angle of the butterfly which is 12.9 degrees. I was eyeballing my rpm at 900 but now I know it's at 960. Which is 200 more that what Vince set it. 

Now, I'm not too sure what to look at? The idle is stable, just high. Not sure what to look for really, all vacuum lines are new. I guess I'll spend my evening reading again! 

[1xshaunx1 27]

Battery voltage looks to be way low. Don’t know about the rest of what you said

[fendervg 29]

It doesn't give you nearly as many options as on a newer car, but you can at least view and clear faults for the engine and for the ABS ECU. It's also possible to monitor a wide range of sensor values - basically nearly every sensor that talks to the ECU will show up in a measuring block.

Are you seeing any fault codes?

High RPM at idle would certainly suggest an air leak somewhere after the maf, or a fauly ISV. I think there is a trick somewhere in the VAG-COM interface for exercising the ISV solenoid - sometimes a proper clean will also help. Check out all your vacuum lines and hoses (to the brake servo, FPR etc.) and the EGR and crankcase breather system - there is also a black baffle muffler box connected to the ISV that often cracks and leaks air.

[fla 9]

I never really got to how the isv is operated via VCDS but (when mine was obd1) i just removed it, sprayed some lube into the flap and pulsed it with a 12v sourced directly on the connections

Hasan

[oneohtwo 8]

The default idle on VCDS should be 720/680 (it flicks between the two), this is the accurate value and reads higher than the dash, which would show 500-600 for this.

Vince upped the idle on mine with the remap as well (he said they do it as standard as it runs a bit better) so I can check what mine reads on VCDS at the weekend if I get a chance and see how it compares. 

[ABV-VR6 12]

9 hours ago, 1xshaunx1 said:

Battery voltage looks to be way low. Don’t know about the rest of what you said

I agree it looks low but I think it is because the car has just idled yet while I check everything. So it won't charge, the fan drains, the after run drains. Weird thing is it shows below 12v on the screen but with the multimeter I get 12.6? I've noticed while idling I only get 13.5 not 14 dot something. Battery is new, alternator too? 

[ABV-VR6 12]

6 hours ago, fendervg said:

It doesn't give you nearly as many options as on a newer car, but you can at least view and clear faults for the engine and for the ABS ECU. It's also possible to monitor a wide range of sensor values - basically nearly every sensor that talks to the ECU will show up in a measuring block.

Are you seeing any fault codes?

High RPM at idle would certainly suggest an air leak somewhere after the maf, or a fauly ISV. I think there is a trick somewhere in the VAG-COM interface for exercising the ISV solenoid - sometimes a proper clean will also help. Check out all your vacuum lines and hoses (to the brake servo, FPR etc.) and the EGR and crankcase breather system - there is also a black baffle muffler box connected to the ISV that often cracks and leaks air.

Thank you mate, I was hoping you would jump in the discussion has I've been reading a lot of your advice about this on the forum. 

So here's where I'm baffled... The idle is steady at 960, not jumping. No codes, no flashing lights. Vince said I settled it at 760 so I'm 200 more. 

So far: I've replaced even if new the isv with 2 more known working ones, same thing. All the vac lines are new. So on idle I sprayed mist of water on isv line, vac lines, after maf, booster and nothing! I'm not sure what to look next to be honest! 

About the vag com, is there a place where all those measuring blocks are written so we know per example 003 is throttle. There must be more? 

[ABV-VR6 12]

6 hours ago, fla said:

I never really got to how the isv is operated via VCDS but (when mine was obd1) i just removed it, sprayed some lube into the flap and pulsed it with a 12v sourced directly on the connections

Hasan

I wish it was just that and it's the first thing that I investigated. But it's new oem, replaced with 2 more since and same idle on all 3...

[ABV-VR6 12]

51 minutes ago, oneohtwo said:

The default idle on VCDS should be 720/680 (it flicks between the two), this is the accurate value and reads higher than the dash, which would show 500-600 for this.

Vince upped the idle on mine with the remap as well (he said they do it as standard as it runs a bit better) so I can check what mine reads on VCDS at the weekend if I get a chance and see how it compares. 

That's true and you are correct. I was wondering if Vince upped the rpm and yes he does it. Sets it at 760. I'm still 200 over... I've investigated all the standard culprit without any luck... If you have time on the weekend, it would be nice to compare for sure! 

[ABV-VR6 12]

7 hours ago, fendervg said:

It doesn't give you nearly as many options as on a newer car, but you can at least view and clear faults for the engine and for the ABS ECU. It's also possible to monitor a wide range of sensor values - basically nearly every sensor that talks to the ECU will show up in a measuring block.

Are you seeing any fault codes?

High RPM at idle would certainly suggest an air leak somewhere after the maf, or a fauly ISV. I think there is a trick somewhere in the VAG-COM interface for exercising the ISV solenoid - sometimes a proper clean will also help. Check out all your vacuum lines and hoses (to the brake servo, FPR etc.) and the EGR and crankcase breather system - there is also a black baffle muffler box connected to the ISV that often cracks and leaks air.

Just to add more, I found more information about the measuring blocs, it's in the Bentley (the only part I haven't read yet) page 01-100

What's described at page 01-88 I would love to do this but does it take VAG 1551 scanner to perform these? 

[fendervg 29]

These should all be possible under Engine, and Output Tests with the full version. VCDS simulates all the functionality of VAG 1551, but in a more user friendly way. However, VAG1551 does have a rather nifty little receipt printer built in ......

 

Edited October 7, 2022 by fendervg

[ABV-VR6 12]

Ya 1551 is definitely a neat machine, kind of like it a lot! I must be old ha haa. Ok mate, I'll check output test and see if I can figure something out.  Thank you for your time and help, much appreciated!