# Yellow Key Symbol on Combi Instrument Panel (KESSY photos and troubleshooting)



## bobinspain (Dec 17, 2010)

Can anybody tell me what the yellow key symbol on the Combi Instrument panel is trying to tell me? My 5cm thick Phaeton handbook does even acknoweledge there is such a thing, and if it did I'll bet it would tell me to take the car to the workshop. 

My tale of woe goes like this: A few days ago we had a tremendous rain storm overnight (similar to tropical rain) whilst my Phaeton was parked in the driveway. I was woken during the night by the car alarm going off. I went out side and functioned the open close with my remote which silenced the alarm. Minutes later it went off again. The same thing happened repeatedly. I eventually decided to try to start the engine cos I have found that will silence any long term alarms. On getting into the car I was deluged with water from above, presumably the sunroof drains had water logged. This performance continued for some time until I decided to disconnect the LHS battery. The alarm continued so I disconnected the RHS battery. Manually opening and closing the drivers door eventually silenced the alarm. 

The next day I investigated to find water in the drive's side footwell and the car was dead. I tried charging the LHS battery for 2 days but eventually concluded it was junk. I installed a new battery but was only able to get the alarm going off repeatedly. 

I have removed the Kessey unit which was wet and the driver's side floor was wet with running water. I removed the PCB from the case and dried it out overnight. Today I have re-installed the Kessey unit but there is little improvement. The dash now lights up, the yellow key sign is still displayed, the car tells me it has synchronised with the key, but as far as starting the engine it is still dead. 

Any suggestions (printable) as to where I should go from here? 

Here's hoping.


----------



## dlouie (Oct 31, 2008)

Bob, 

I think the key icon and the car not starting are related to same issue. It's encouraging that after drying out the kessy, everything appears to be functioning except that. The car is trying to tell you that the RFID chip in your key is not recognized, either not detected properly or doesn't match what is programmed. One should never try to power up an electronic device that has been water logged! Others will surely chime in on this but I recommend that you try to do a scan of the car first. I have hope that the kessy may be salvageable. I wonder of the mosfets or fuseable resistors were blown when you tried to start the car. 

Damon


----------



## bobinspain (Dec 17, 2010)

Thanks Damon that's more encouraging. The problem with scanning the car (I do have a VSDS) is that it will not let me switch on the ignition to make the car live. Any suggestions? 

Bob


----------



## perfrej (Dec 24, 2009)

"Water ingress in left footwell"... Check table of contents - there is a specific thread about this. It affects the authorization system which is... In the left footwell! 

Water gets in either by sunroof drains or A/C. 

/per


----------



## Paximus (Aug 26, 2011)

The procedure for getting a new KESSY up and running is reported to take the dealer several hours of programming labour, including overcoming the chicken and egg situation that they can't start the car to operate the KESSY until the factory master security key is established in the KESSY in order to switch it on so that they can reprogram the ECUs and the ABS controller in order to fire up the ignition and establish the KESSY ready to program your set of key fobs so that they can start the car and program the KESSY...  

So it's worth having a close look at the old one to see if the power FETS that drive the security antennas and ignition key chip sensor are OK, as per Damon and Per's suggestions. And even a physical check of the relevant fuses might pull that rabbit out of the hat! 

Chris 


[Edit -  I have just been told by an expert who has done it that the KESSY unit can be replaced with only normal programming effort. The SSP says that any one of these items can be replaced: KESSY/ECU/ESL/Key but a second replacement from that list requires more heavy duty programming to reset the CAN-Bus security codes.]


----------



## PanEuropean (Nov 3, 2001)

bobinspain said:


> Thanks Damon that's more encouraging. The problem with scanning the car (I do have a VSDS) is that it will not let me switch on the ignition to make the car live. Any suggestions?


 Depress the brake pedal and hold it depressed for 20 seconds. This will wake up the communication busses so that you can scan the car. 

Michael


----------



## WillemBal (Nov 20, 2010)

bobinspain said:


> I removed the PCB from the case and dried it out overnight. Today I have re-installed the Kessey unit but there is little improvement.


 Hi Bob, 
We communicated via PM this morning, and I can indeed try to see whether I can bring it back to live. But just a word of advice for you and next persons who read this. 
Most electronics, including the KESSY, are amazingly resistant to water ingress. In the case of the KESSY, the car may act funny, i.e. it may notoriously trigger the alarm horn, flash lights; it may try to start the engine, resulting in smoke development and ultimately set the engine compartment on fire, but the KESSY may actually survive all these disasters. . 
Taking out the PCB and let it dry may actually damage the electronics though. Really the best thing is to let it drip out most of the water, leaving the PCB inside its casing, and then wrap it up in a plastic bag and seal it so it can't leak during transportation. This will prevent damage as the result of drying out. 

Please let me know whether you have the keyless access and start function (identifiable by the presence of the small buttons on the outside door handles) and the start button next to the shift lever. 
I cannot test all functions, but can test some vital components, i.e. the power FET's. I can also pre-emptively replace the FET's for the antenna's. I then send it back to you for testing. 
I hope it will be a success. 

Willem


----------



## bobinspain (Dec 17, 2010)

Thanks for the advice Willem. 

Yesterday was another very wet day here in "sunny" 6 deg Spain and the car is stuck out in our driveway so nothing was done. I plan to try Michael's suggestion this morning and if nothing happens I will remove the unit and send it off to you tomorrow morning. 

Regards Bob


----------



## bobinspain (Dec 17, 2010)

Willem, 

I didn't complete the message. I do not have keyless access and start. 

Bob


----------



## WillemBal (Nov 20, 2010)

Yesterday, I received Bob's KESSY via mail and first inspected it. The board looked pretty rough, compared to a new one. In the below photo, you can see what the water ingress had done to your board: 










And some more damage below: 










Normally, the board should only have two shades of green, light and dark green. Where you see the whitish/blueish shades of green, the water has deposited and formed salts. These salts are partly conducting, messing up the functionalities of the electronics. After using a combination of chemical and mechanical methods, I got the result below: 










Some more effort was needed to fix the problems inside the metal casing. For shielding purposes, both the shield and the board underneath were pretty rigidly soldered to the board. But it is "as new" now. 
No components were replaced this time, as there was no sign of other damage. Interestingly, Bob's board is a little different than others. This one doesn't appear to have a lot of "power" electronics the difference is most obvious when you compare the above photo with the photo of a KESSY I fixed a year ago: 










As you can see, the MOSFET's are not present in Bob's board, as well as the transformer, a bunch of capacitors and a lot more additional parts. 
Bob's KESSY has the same part number as others, but has suffix "J": 3D0909135J. Bob's car hasn't got the keyless access and start, so perhaps that accounts for the difference. 

So, KESSY is on its way back now...I hope that it is going to work. It would confirm my feeling that the dried salts and corrosion causes the problem and that all components are still functional. 

We'll wait and see... 

Willem


----------



## Paximus (Aug 26, 2011)

:thumbup:


----------



## PanEuropean (Nov 3, 2001)

Wow, awesome investigation, write-up, and photos.

Thanks very much Willem.

Michael


----------



## PanEuropean (Nov 3, 2001)

*Archival Note:*

See also this discussion: Repairing the Access and Start Controller (controller 07) - resolving antenna 'open circuit' faults.

Michael


----------



## WillemBal (Nov 20, 2010)

PanEuropean said:


> Wow, awesome investigation, write-up, and photos.
> Thanks very much Willem.Michael


Thank you for your kind words, Michael.
The KESSY returned to Bob late Monday afternoon and we have been discussing by PM about the outcome after re-installing it. 
Originally, there was little improvement (Monday evening). But yesterday, Bob sent me some good news in the form of the following message:



> Last evening I left the car powered up. This morning as I was leaving the house I noticed the red security lights were flashing on the drivers and passengers doors. I have just arrived home and am now able to open/close the car using the buttons on the key fob and on locking the car now beeps at me to tell me all is secure. I would say that tells me the Kessy is now working OK. That's the good news.
> 
> I still can't get the system to give me an engine start or turn on the ignition. The yellow key symbol is still showing and the ignition switch captures the key. The info system syncs with the key OK so that would indicate the chip in the key is OK. I can get rid of the key symbol by depressing the brake pedal and remove the key using a pencil to depress the ignition switch lock.
> 
> Any ideas?


Basically, it implies that the KESSY is working and fulfils most of its functions. It is watching burglars, opens and closes doors which means that it is already 99% operable. It can communicate via CAN, it can send and receive RFID messages to and from the keyfob and unlock and lock the doors.

The yellow key symbol does ring a bell as I just discovered yesterday that this MIGHT indicate that the car is requesting an emergency start. This can happen when one of the batteries is below a certain threshold voltage. Indication of this situation is by means of either one of the following pictures:










OR:










Bob,
To start the engine, it is necessary that you use the key and not the start button (if you have it at all). After you have turned it to the ignition position, please turn it to the neutral position, then turn to the left until it goes no further. This will arm the Emergency Start Procedure, allowing you to start the engine by turning the key to ignition, then start, or simply directly to the start position.
Please do not wait too long after turning the key all the way to the left, as the Emergency Start Procedure may only available for a limited time, say 15 seconds, to conserve the energy left in the batteries. To prepare yourself what you might eventually see, please check out *THIS POST*, where the entire procedure is explained.
WARNING: Do not disconnect the LH battery like I did during that sequence. I only did so for the sake of the experiment. 

Willem


----------



## Victor R (Jan 7, 2010)

FYI,

The yellow key symbol also shows when the battery in the FOB needs replacement.










Once the initial message disappears, the screen is indistinguishable from one seen after the "System Fault Workshop" message disappears.










I had the system fault workshop screen appear after I let my car sit for a while in the winter. The problem turned out to be due to a NAPA AGM battery that had been installed as the left hand battery in the car rather than an OEM VW one.

Victor


----------



## bobinspain (Dec 17, 2010)

Hi folks,
Sorry for the silence from me during the past few days, otherwise engaged with family issues.

I think Willem has updated this thread quite nicely. As of this evening I am in the same place as three days ago following receipt and installation of the repaired Kessy from Willem. It does seem that the car sitting overnight helped and as far as I can tell the repaired Kessy is working fine, security system and remote key fob operations wise except it still will not start. The yellow key symbol together with the System Fault - Workshop (in yellow) warning shows and the key gets locked into the ignition cylinder. I can get rid of the warning by depressing the brake pedal as suggested by Michael and I can remove the key by using a pencil to depress the button to the right of the key whilst turning anticlockwise, but nothing else happens, including releasing transmission shifter which remains in the park position.

At this time I am charging the emergency battery overnight just to see if it is low voltage in that circuit which is causing the problem since I have previous experience with low voltage load shedding caused by LH battery draining when the car is unused for some period.

Other than that ....any suggestions?

Bob


----------



## WillemBal (Nov 20, 2010)

bobinspain said:


> The yellow key symbol together with the System Fault - Workshop (in yellow) warning shows and the key gets locked into the ignition cylinder. I can get rid of the warning by depressing the brake pedal as suggested by Michael and I can remove the key by using a pencil to depress the button to the right of the key whilst turning anticlockwise, but nothing else happens, including releasing transmission shifter which remains in the park position.


Hi Bob,
Perhaps you did not yet try the "emergency" start procedure.
When you see an amber message, it is normally not that critical that it cannot be solved without dealer intervention. When you see a message like the one I posted, i.e. the amber key symbol with underneath the text "System Fault Workshop", it is probably the result of a discharged LH battery. This particular battery is called the convenience battery, but that is a bit of a misnomer, because it in fact delivers power to ALL controllers in the Phaeton. It is located at the left hand (LH) side of the trunk.
At the right hand side of the trunk, the RH battery is located. This is the starter battery and its sole purpose is to start the engine. Under normal circumstances, you need BOTH batteries to start the engine.
When the LH battery is empty or below a certain threshold, presumable 11 Volts, a turn of the key to ignition will give the amber key symbol.
There is a way to treat it, which is called the "Emergency Start Procedure", which can be armed by turning the key fully counterclockwise until it stops, then back to ignition and crank position.
But before you are going to try this (from what you wrote, I understood you did NOT try it yet), please take care of some other crucial actions, described below.



> At this time I am charging the emergency battery overnight just to see if it is low voltage in that circuit which is causing the problem since I have previous experience with low voltage load shedding caused by LH battery draining when the car is unused for some period.


[/QUOTE]

After reading this, I'm not 100% sure whether your charging method is right. The 2 batteries in the trunk are called convenience battery (LH) and the starter battery (RH side of the trunk).
For a start, please do NOT attempt to charge a battery by connecting your charger clamps to the jump start post under the hood. 
Instead, please open the trunk and remove the left panel which covers a battery and a fuse box. Connect your charger clamps to that battery and leave it overnight. Also leave it there when you attempt to start the engine the next day.

The next day, when you again try to start the car, assuming the LH battery is full (hopefully you have a DMM to verify this), please work your way through the following steps:



Insert the key and turn clockwise to ignition. (as usual)
When you *still* see the workshop message, don't be desperate, don't give up, but instead, turn the key *fully counterclockwise*, which means: THROUGH the position where you would normally be able to take out the key.
Within a couple of seconds after completing the previous step (the amber message won't disappear), please try again to start the engine as usual. There is no need to rush things, but please do not wait too long...the car will only allow to be started during the next couple of seconds. Just turn the key fully clockwise while you have your foot on the brake pedal, as usual.


I'm pretty sure that there will be success this time. There is a small chance though, that the KESSY is loaded with DTC's preventing you to start the engine. However, the yellow key / workshop message indicates that the problem needs attention, but is not crucial. So recharging the LH battery via the trunk, eventually followed by the "Emergency start" procedure as indicated above, is most likely going to solve the problem.

Willem


----------



## bobinspain (Dec 17, 2010)

Hi Willem,

Sorry to say I have tried the emergency start, it is a procedure I have used in the past when the LH battery drained after the car was left unused for some time. I have previously charged the battery and am familiar with that.

What happened during the alarm / flooding event seems to have been so violent that it damaged the LH battery to the extent that I have replaced it with a new one. This also makes me feel that there could be some other component in the system/s that has/have been damaged. I have checked all the fuses and can't find anything wrong there but am now wondering whether a relay could have been fried. In my mind this is supported by the "dead" reaction, ie nothing at all, except the yellow key symbol and fault message, when I try to start the car and turn the key to bring in the emergency battery. I am assuming there are relays in both the normal start and emergency start switch over systems. Can you tell me which and where those relays (if any) are and if it is easy to tell if they are damaaged?

Bob


----------



## WillemBal (Nov 20, 2010)

Hi Bob,
It looks like the rain in Spain falls mainly in your plane!
The main fuse/relay box is located in the LH side of the trunk, right above the battery. You can recognize the relays easily, they all have numbers on them and are located in the upper left corner of the fuse box. You can take out the fuse box.

Unfortunately, most of these fuses are energized by the KESSY. To name a few:
Relay 1 - J579 Electrical System Battery Switch-Over Relay (Relay is energized by Kessy)
Relay 2 - J580 Starter Battery Switch-Over Relay (Relay is energized by Kessy)
Relay 3 - J682 Power Supply Relay feeds Starter. (Relay is energized by Kessy)
The above are "SC" relays, in the LH side of the trunk as mentioned above. Number 1 is upper left, number 2 next to it, etc.

J581 Parallel Battery Connection Relay is energized by Battery Monitoring Control Module. It is located at the RH side of the fuse box in the LH side of the trunk. It looks like a motor, but it is a fuse. It is only energized when the starter battery is drained. It is so big because it has to carry >>100 Amps during cranking. I'm sure it is not related to your problem

Some other important relays are located in the Electronics Box in the Air Intake Plenum Chamber:

Fuse 6 - J680 Power Supply Relay Feeds Electical System Control Module (Relay is energized by Kessy)
Fuse 8 - J329 Voltage Supply Terminal 15 B+ Relay (Relay is energized by Kessy)

Actually, unless the whole trunk has been under water, I have a feeling that there is nothing wrong with your relays. They are all energized by the KESSY (that is... pulled to ground when energized). So the KESSY is still suspect.

The troubleshooting might be a lot easier if you can use your VCDS. Michael indicated that you need to depress the brake pedal for at least 20 seconds to fire up the OBD-II of the instrument cluster. I think, but I'm not sure, that you also have to turn your key to ignition. In other words, you need some life in the instrument cluster to breath life into the OBD-II adapter, so your VCDS tool can properly communicate with the controllers. If you can, make an auto-scan. If this is not possible, then try to access the KESSY directly via "Select Controller".

Willem


----------



## bobinspain (Dec 17, 2010)

Hi Willem,

Thanks for the info. Is there anything obvious about a relay that tells you if it is fried or otherwise damaged ? I also understand that there is another fuse box in the plenum chamer which I will check as soon as I can some time freed up.

I have tried the foot on the brake pedal thing both with the ignition off and the key aligned 0600 - 1200, and with the key turned fully clockwise, for well in excess of 20 seconds. It gets rid of the yellow key alarm but does not liven the system up. What I do have is the security (door lock/unlock, etc) and centre consol working. Is that sufficient to be able to do VDSC scan? I thought I would need the ignition on for that.

Bob


----------



## PanEuropean (Nov 3, 2001)

bobinspain said:


> I also understand that there is another fuse box in the plenum chamer which I will check as soon as I can some time freed up.


Bob:

There is a picture of that fuse box (opened up) at this discussion: Electronics Box in Right Plenum Chamber . But, before you go in there and open it up, please carefully read post #12 of that discussion, and read the TB that is attached. You might want to consider going to your local VW dealer and ordering the parts described in the TB (quantity 2 of 3D0 971 838M) so that you have the parts on hand and can correctly seal up that box after you look in it.

If you get water in that box later on because of an improper closure, you will be in for a world of hurt.

Michael


----------



## bobinspain (Dec 17, 2010)

Thanks for the warning Michael.

I had a thought during last night. So far I/we have been concentrating my/our attention on a possible problem with the car, maybe the problem is with the key. During the night of the wet event stopping the car from alarming was very difficult and took some time with having to eventually disconnect the batteries before it would cancel and stay quiet. I just wonder if is possible that the car system is clever enough to identify the key and consider it to be a rogue or partially damage the firmwear in the key. I will add that the Infotainment system in the car does still recognise the key.

If anybody has any ideas regarding the potential of the key being my problem I will be pleased to hear from them. The ideas I have range from the possibility of temporarily rigging the system to get round such a problem, through taking the key to the dealer where they may be able to mend the problem (if any) to buying a new key.

Here's hoping

Bob


----------



## Victor R (Jan 7, 2010)

I don't think it is the key.

When the key is not right, this is the way the display looks on the infotainment system. After that, it goes totally black.










Victor


----------



## PanEuropean (Nov 3, 2001)

*Archival Note:*

A complete explanation of the DIN (German Industrial Norm) coding for vehicle electrical power supply - in other words, decoding of what "terminal 15", "terminal 30", etc. means - can be found at this Wikipedia entry: DIN 72552 - Standard for automobile electric terminal numbers.

Michael


----------



## WillemBal (Nov 20, 2010)

bobinspain said:


> ....I will add that the Infotainment system in the car does still recognise the key....


Do you mean to say that the infotainment system lights up and tells you the ID number and name of the key? That's interesting. As far as I know, the key recognition works through the KESSY, which sends out an RFID code, which is responded by the RFID chip in the key with a unique and constant code. The key is then identified and possibly already reported on the infotainment system. However, the immobilizer system wants to be sure that it is really your key which is responding and not a copied code (by a car thief). For the purpose of verification, the KESSY sends out some random number, which is processed by the key after reception. An internal algorithm computes the outcome and sends the result back to the KESSY. This process is comparable to when you transfer funds from your bank account, using a chip card, a card reader and of course internet.

So it could be that the identification process is carried out all right, but the verification process, for which the keyfob needs to compute a result, is failing. It looks like a problem only a dealer can solve. For verification of this process, it needs to gain access to both the car and all your keys. Also, they will need to establish a secured online connection with headquarters in case they want to reprogram your existing keys or kessy or both.

NOTE: On page 62 of "The Phaeton - Onboard Power Supply and Function", there is a description of various yellow key messages. One of them says: 
"ID sender not detected". According to this document, it can cause a message like "System Fault, Workshop!". Hopefully a VW dealer nearby can help you out. It needs to be towed though. 

Willem


----------



## PanEuropean (Nov 3, 2001)

Bob:

If you do take your car to a VW dealer for further investigation of the problems you are having, be sure to bring *ALL *the keys you possess. When any new or existing key is adapted (or re-adapted) to the vehicle, all other keys must be re-adapted at the same time. Any keys not present during the adaptation process will be disqualified and will no longer work.

Michael


----------



## bobinspain (Dec 17, 2010)

Hi Willem and Michael,

Sorry for the 2 day silence.

The P, although I now have new word for it, left the house this morning onboard a flat bed truck. Getting it out of my driveway and onto the truck was interesting, I learned some new Spanish words, they used 4 roller skates and towed it using the truck's winch plus some steel remnants from my workshop. Following siesta time it should arrive at the dealer in Alicante this pm. I will keep you posted once I have some news from the dealer. Probably mañana ! By the way, the use of flat bed trucks is normal in Spain 'cos its illegal to tow vehicles on public roads.

Bob


----------



## bobinspain (Dec 17, 2010)

Hi, I'm pleased to say my "P" is now back home and running OK following a prolonged stay at the local VW Main Dealer in Alicante. Some of the delay in getting the car sorted was down to the Fiestas around Xmas time, fortunately I missed the 3 Kings Fiesta which happens this evening.

The problem was the kessy which has been replaced although they did go through the process of diagnosing a possible key/ignition switch problem. The ignition switch was replaced but there was no difference so the original one was put back, then I managed to get through to them about the water, etc, and their efforts were directed to the kessy.

I really need to thank all the people who contributed to this thread, especially Willem.

Just a by-line. If you suspect you have a kessy which is fragile make sure you park your "P" in an accessible position for a flat bed truck.


----------

