# Guided Fault Finding in VCDS, now or in the future?



## Anony00GT (Mar 6, 2002)

I've run into a few newer Audi vehicles now where, in order to perform diagnosis, the service info says to use guided fault finding in the scan tool, rather than publish the diagnostic path in the manual.

So far it hasn't been a big issue, but I'm afraid it could turn into one (at least for me) in the not-so-distant future. I know BMW has been doing this for some time, now I assume VAG is going in the same direction. Just wondering if VCDS supports, or will support, this? Or is it something that's gotta be done online through ErWin with a genuine VW tool? Any info from the team at RT?


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## jyoung8607 (Feb 14, 2006)

Anony00GT said:


> I've run into a few newer Audi vehicles now where, in order to perform diagnosis, the service info says to use guided fault finding in the scan tool, rather than publish the diagnostic path in the manual.


Pretty much all newer cars are ""documented"" this way now in the factory manuals. 



Anony00GT said:


> Just wondering if VCDS supports, or will support, this? Or is it something that's gotta be done online through ErWin with a genuine VW tool?


Depends on what it is. GFF is the name for a bunch of wizard-like scripts that hide the real underlying tools from you. Some of it is useful, some of it is stifling and unusable. Understand that VCDS already does a lot of what GFF does for coding (tooltips, the Long Coding Helper) and other functions, better and easier. Other major parts of GFF are troubleshooting scripts a dealer tech must follow and document in order to get paid on warranty claims. The usefulness of this function is, shall we say, hotly contested.

There are some things, like Immobilizer key matching, which VWAG have chosen to lock up so that no third-party can implement them, and that's just how it is.

Is there something specific you're trying to do?

Jason


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## Anony00GT (Mar 6, 2002)

No, nothing specific at the moment. I know exactly what GFF is, I've used it before in dealership settings. I realize that VCDS has the ability to do everything (except immobilizer) without the script. This is why I haven't had an issue with it (yet). Maybe I won't, who knows. But as a professional repair shop, I like to be prepared. Most of the vehicles I see are 3-10 years old; they don't come to me until the warranty has expired.

What are tooltips?


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## bearthebruce (Dec 23, 2005)

Fundamentally, Ross-Tech has issues with the concept of Guided Functions. The Guided Functions were implemented to take the technician's knowledge out of the equation by forcing consistency in troubleshooting methods. The tool user follows an engineer's educated guess at what might cause an underlying problem. Often Guided Functions leads to misguided part replacements - replacements that are unnecessary and do not end up resolving the problem. Philosophically, we do not think replacing parts that have not failed is a proper method of resolving issues. Instead, we have chosen to try to include information by which the technician can discern the "right path" to resolve problems. Rather than living in the Borg collective, we choose to allow the technician to build their skill and use the knowledge they possess to hone in on a proper solution. 

Short answer: we have no plans to implement GFF.

There are some procedures that VAG is implementing which can only be done with GFF. The number of these in each model year are increasing. How we will address these remains an open design issue. Most to date have not had impact on general repair service. They have been implemented on the Immo, ABS, Airbag systems. These procedures operate like the more recent model Immo functions where the tool, the factory server, and the car carry out the procedure without the technician having a clue as to what is being done in the process.

Do we think this is the way things will continue to move? Yes. 

With the Right to Repair agreement that was worked out, all OEs have to allow the aftermarket repair facilities the use of a J2534 pass through tool to perform diagnostic procedures. Early on, VAG allowed a low cost entry into using their ODIS software. This year, significant price increases have been announced.

Where do we think this is going? Right back to where it has always been. As my father wisely taught me, follow the dollars..... Then you get idea of what is truly in play.


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## krisco1996 (Jan 13, 2015)

bearthebruce said:


> Fundamentally, Ross-Tech has issues with the concept of Guided Functions. The Guided Functions were implemented to take the technician's knowledge out of the equation by forcing consistency in troubleshooting methods. The tool user follows an engineer's educated guess at what might cause an underlying problem. Often Guided Functions leads to misguided part replacements - replacements that are unnecessary and do not end up resolving the problem. Philosophically, we do not think replacing parts that have not failed is a proper method of resolving issues. Instead, we have chosen to try to include information by which the technician can discern the "right path" to resolve problems. Rather than living in the Borg collective, we choose to allow the technician to build their skill and use the knowledge they possess to hone in on a proper solution.
> 
> Short answer: we have no plans to implement GFF.
> 
> ...


Well said sir!! This is probably one of the most professional posts I have ever seen. Props to you sir.


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## Anony00GT (Mar 6, 2002)

bearthebruce said:


> Short answer: we have no plans to implement GFF.
> 
> There are some procedures that VAG is implementing which can only be done with GFF. The number of these in each model year are increasing. How we will address these remains an open design issue. Most to date have not had impact on general repair service. They have been implemented on the Immo, ABS, Airbag systems. These procedures operate like the more recent model Immo functions where the tool, the factory server, and the car carry out the procedure without the technician having a clue as to what is being done in the process.


Thanks Bruce. This is exactly what I'm referring to, and pretty much answers my question.


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## JSWTDI09 (Feb 22, 2009)

GFF (Guided Fault Finding) is a great way to sell parts. It is a tool to allow untrained (or under-trained) technicians to work on cars they know little or nothing about. It only tells a dealer tech which part(s) to replace. It is often not very smart, so it often tells them to replace perfectly good parts until it finally finds the part that is actually bad. GFF has wasted more customer money that just about anything (or anybody) else at a VW dealership. I would not want GFF for my car unless there was a way to make it much smarter. Telling me to swap out parts without doing the troubleshooting to determine that they are actually bad is (at best) a waste of time and money. I prefer to have VCDS tell me what the car thinks is bad, then I start troubleshooting to figure out why that fault code occurred. A fault code does not necessarily point to a bad part, it only points to an anomalous sensor reading somewhere. A competent troubleshooter must then figure out why that sensor was giving the wrong reading. It could be a bad sensor, or it could be at least a dozen other things - why start by replacing the sensor?

Have Fun!

Don


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## Anony00GT (Mar 6, 2002)

JSWTDI09 said:


> GFF (Guided Fault Finding) is a great way to sell parts. It is a tool to allow untrained (or under-trained) technicians to work on cars they know little or nothing about. It only tells a dealer tech which part(s) to replace. It is often not very smart, so it often tells them to replace perfectly good parts until it finally finds the part that is actually bad. GFF has wasted more customer money that just about anything (or anybody) else at a VW dealership. I would not want GFF for my car unless there was a way to make it much smarter. Telling me to swap out parts without doing the troubleshooting to determine that they are actually bad is (at best) a waste of time and money. I prefer to have VCDS tell me what the car thinks is bad, then I start troubleshooting to figure out why that fault code occurred. A fault code does not necessarily point to a bad part, it only points to an anomalous sensor reading somewhere. A competent troubleshooter must then figure out why that sensor was giving the wrong reading. It could be a bad sensor, or it could be at least a dozen other things - why start by replacing the sensor?
> 
> Have Fun!
> 
> Don


I agree with your principle here, but I disagree about GFF. Then again I've never had the privilege of using VAG's GFF, only BMW's. I can tell you that it certainly did NOT just tell us what parts to replace, but rather, it walked us through a complete diagnosis step by step. It was, in essence, forcing us to follow the complete flowchart to PREVENT techs from just throwing parts at cars. It was designed to keep parts replacement costs down in warranty situations. The downside (from a diag perspective) is that sometimes the exact flowcharts aren't the fastest or most efficient way to pinpoint a problem. Of course, there were also the techs who told the tool "yeah I checked that wire" when they really didn't (that's where the misdiagnosis comes from, not the tool).

The real downside is that there are often only minimal fault diagnostic info in the service manuals, sometimes none at all. Rather, you were forced to go through the test plan in the GT1 to get any diag info at all. BMW just doesn't publish much outside the scan tool. My fear is that VAG is headed in that direction and we might not have access to any diag info without the OE scan tool and GFF. As a DIY person it might not be a big deal, but as a professional repair shop that sees tons of VAG cars, it could become an issue that results in a great expense increase in the not-so-distant future.


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## nick31 (Jul 22, 2013)

You can always get chinese VAS5054a with software for around $100 and GFF will be there as well.


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## VWShadeTree (Jun 14, 2015)

I've been wondering about this exact thing; I was lucky to find this thread, and I can't believe how recent it is. A quick internet search on this exact topic a month or two ago didn't produce any satisfying answers so I let it go until now.

As a DIYer with a primary motivation to steer clear of dealerships this is all very relevant to my situation. Prior to my entry into VW repair I didn't have so much trouble finding service information; I was quite surprised when I purchased the Bentley printed service manual for my vehicle and read that the information I needed wasn't available in printed format, I'd have to run software for that. Well, I was surprised the first time I came across that tidbit, not so much the second and third time...

Two months ago was the first time I saw instructions to run GFF as opposed to being provided with actual, real service info, so this whole concept of GFF just throws another wrench into the gears because it's obscuring data from me. From my point of view I certainly wish VCDS did support as much GFF as possible if for no other reason just so I can try to know what I don't know now. Stepping through a GFF routine a few times might expose valuable information unattainable any other way, so I'd rather see VCDS support it with a disclaimer beforehand regarding the effectiveness of GFF and part replacement solely based on GFF than have VCDS not support it at all.

_My previous example: I have a 2007 MkV Golf (Rabbit). Went to replace valve body, no info in printed Bentley service manual. Had to find information elsewhere, not desirable at all._

Current issue (any insight would be appreciated): The LED on my door flashes seven times every time I lock the doors - didn't used to do that. Tracking the relevant info through the service guides led to the generic "Run GFF to determine the problem" message. So now I'm stabbing in the dark. Does VCDS have any existing functions to help me in this case? Does anyone have info or a link to info regarding flash codes for the MkV anti-theft system?

Thank you Anony00GT for the awesome post and thanks to everyone for the beneficial discussion.


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