OBD II diagnostic port does not work (major electrical power shortage)

[VWGlf00GL]

Good Evening Phaeton Gang!

It's been a while since i've posted, well, because the Phaeton has been running well these days.. I took my car in last week for service, the foreman/technician completed the maintenance 60,000 maintenance schedule. He couldn't use the VAS 5051 connect the car to diagnose any DTC's or reset the "SERVICE NOW" on the screen. I've yet to bring the car back in for a few small things..

I plugged in my buddies USB VAG-COM cable with mini Acer Laptop, the cable's green light won't light up (signaling a connection between the car and computer). Car ignition was in the ON position, I also started the car too and left it running for a few minutes before we plugged the cable in.

We took that same USB VAG-COM cable and mini computer to his 2001.5 Passat Wagon and plugged everything in, just fine. It lights-up, and the software starts to read the car.

What's up with the Diagnostic Port? The tech can't get it to work, we can't get it to work? He really does not like to work on the car if he can't read the computers/controllers for DTC's or pending codes.

What do you think it might be?

Thanks guys and gals!

- Adrian

[PanEuropean]

Hello Adrian:

I believe that there is a fuse in the front fuse panel that supplies power to the OnBoard Diagnostic (OBD) connector. I think it is fuse 27, but don't take my word for it - there is a list of fuses, fuse locations, and what the fuses are for in the back of your owner manual. Just look in the index of the owner manual for the word 'fuse' and you will find the page number that contains the list.

I think that if no power is supplied to the pin on the OBD connector that is supposed to have power, the diagnostic tool will not work.

It is also possible that you may have another more complex electrical problem that relates to the immobilizer in the vehicle. If you have seen any evidence that that might be the case, then press and hold the brake pedal for 20 seconds. That will then supply power to the OBD connector.

Michael

[mrsharkbait]

Quote, originally posted by PanEuropean »

... press and hold the brake pedal for 20 seconds. That will then supply power to the OBD connector.

Michael,

If there were a Trivial Pursuit game for VWs, you would be the clear winner. I'm just amazed.

e

[VWGlf00GL]

Quote, originally posted by PanEuropean »

Hello Adrian: I believe that there is a fuse in the front fuse panel that supplies power to the OnBoard Diagnostic (OBD) connector. I think it is fuse 27, but don't take my word for it - there is a list of fuses, fuse locations, and what the fuses are for in the back of your owner manual. Just look in the index of the owner manual for the word 'fuse' and you will find the page number that contains the list. I think that if no power is supplied to the pin on the OBD connector that is supposed to have power, the diagnostic tool will not work. It is also possible that you may have another more complex electrical problem that relates to the immobilizer in the vehicle. If you have seen any evidence that that might be the case, then press and hold the brake pedal for 20 seconds. That will then supply power to the OBD connector. Michael

Hello Michael!

No Go! I did not pull any fuses, well because I was scared too. Depressing the brake pedal for 20 seconds does nothing.. Now something else is quirky with the car..

1. The analog clock light sometimes stays illuminated. The time resets to 12am and 1/1/2000 when the car is restarted. Turn ignition off, then turn it back on.

2. The RPM's needle goes in reverse when the car is restarted too, power cycled as well. I don't know what the heck is going on now. They "stick" in their positions when the car is turned off.

I just got home, turned the car off the analog clock light is now off. So I'll give it till overnight to "sleep on it". I take car in tomorrow morning 9:00 am..

The car runs fine.. No CEL, no problems with any additional lights/functions.. I tested just about every button in/around the car.. Everything else works just fine..

I think I am going to ask about a "capacitive discharge" tomorrow morning. This was done mid last year when the temp gauge wouldn't move, it was stuck.

Video of issues: http://www.youtube.com/watch?v=dEy7UWxYMjw

(Sorry bad blackberry cell phone camera)


Modified by VWGlf00GL at 9:48 PM 4-9-2009

[Reflect]

You need the new update since you have an 04. tell teh dealer your problems and they will tell you its nothing wrong. then you tell them to call VW and explain you need the TB since you have glitches.
It takes 2 hrs and the VW tech does it online or tell the tech what to do.
I did this and its great now, many lil things fixed, including weird music sounds.

[PanEuropean]

Adrian:

Everything you have written - including the video you posted - suggests that there is a very serious lack of electricity to the vehicle once you turn the ignition off.

I don't know how or why this would happen - the fact that you apparently don't have any power at the OBD connector (as well as the fact that you obviously don't have power to the clock when the ignition is turned off) very strongly suggests that there is no power coming from the left battery (the comfort battery) to the various vehicle services that are normally provided with hot battery bus power (Terminal 30 power, in VW-speak) when the ignition is off.

So, start your troubleshooting at the left battery, simply because that is the most probable cause (you have a 6 year old car) and it is the easiest component to diagnose. With the ignition off, measure the voltage at that battery. Your VW dealer will have a specialized tool called a Midtronics battery analyzer. Disconnect the positive terminal of the left battery (you can leave the ground terminal connected), hook up the Midtronics tool to the battery, and run a test. Odds are that the battery has come to the end of its life and has no juice left in it. If you have found in the past that you have to twist the ignition key back and forth to start the car, then FOR SURE your left battery is toast.

Midtronics Battery Analyzer hooked up to left battery
Disconnect the positive cable from the battery first!

Sample of the reports provided by the battery testing tool.
This takes all the guesswork out of concerns about the battery itself.

If the left battery passes the test and is found to be satisfactory, then there is a fuse blown somewhere in your car - perhaps not one of the little itty-bitty fuses that we as drivers can access, but one of the larger 'bus feeder' fuses that provides battery power to the vehicle systems when the ignition is off.

The next thing to do is an investigation into power supply at various sources in the vehicle. For example, the dome lights are normally powered when the ignition is off. Check to see if the dome light illuminates when the door is opened. If it doesn't, then you have a shortage of hot battery bus (terminal 30) power.

The analog clock has no time-keeping ability, it is just a little stepper motor, nothing more. The clock receives one impulse a minute (via the CAN bus) from the J523 Front Information Display and Control Head, which is that big display screen between the two front seats. The J523, in turn, gets some electrical power from the J519 Central Electrical Controller. This is not rocket science, it is laid out very clearly in Phaeton electrical diagram 30 (for the clock), and diagram 08 (power distribution for dual battery vehicles, both of which your VW technician has easy access to.

Basic principles of troubleshooting dictate that if electricity is not present when it should be present, you go looking for the interruption in the circuit - you don't get out your eye of newt and toe of frog and start hocus-pocus such as "capacitive discharge" ceremonies. I mean, it’s painfully obvious that there is no friggin' electricity present to discharge, for Pete's sake, a shortage of electricity the root cause of the problem! I am quite skeptical of this "capacitive discharge" proposal. I don't think it will do any more good than making a Sign of the Cross anytime you walk past a graveyard, or wearing an amulet around your neck to ward off the evil eye.

The J523 (controller 07) is normally supplied with operating power from fuse SB 17, which is in the fusebox underneath the steering wheel. The J519 (controller 09) gets electrical power from numerous fuses, including SB 10, 11, 12, 13, and 14, all of which are also in the fusebox underneath the steering wheel. The instrument cluster (controller 17) gets power from fuse SB 54. As you have probably figured out by now, if a fuse (Sicherung in German) has a B after the first letter, that means the fuse is in the panel under the steering wheel.

Begin the troubleshooting by pulling each fuse out and inspecting it for continuity, either visually or (preferably) with an ohm meter. While you have the fuse out, select the volt meter function of the electrical tool and check to see if there is power present on the bus (source) side of the fuse holder. I can tell you with almost total certainty that you are probably not going to find Terminal 30 (hot battery bus) or Terminal 15 (power when starting) power on the bus side of those fuse holders. If you check two of those fuses in a row and discover that the fuse itself is in satisfactory condition but there is no power present on the bus side of the fuse holder, it’s time to work your way upstream towards the power source.

There is a fuse box (not a panel, but a box) present in the left battery compartment, and it contains 4 very high amperage fuses (see picture below). Fuse S205 (the second fuse in that box) just happens to be the one that feeds all of the little fuses I mentioned in the previous paragraph. Fuse S207 (the first fuse in that box) just happens to provide Terminal 30 power (battery power) to the J523. If your left battery was found to be satisfactory during the first step of the troubleshooting process, then I suspect that one or more of those fuses have blown.

Fuse box (not panel, but BOX) for high amperage fuses

It is not easy to get access to that high amperage fuse box. To do so, the technician has to remove the fuse panel that is directly above the battery from its backing plate, then remove the backing plate from the holder that it snaps into. If the technician has done this several times before, it is about a 2 minute job. If the technician has not done this before, it will be a very frustrating task and he or she will probably wind up breaking some plastic parts. So, refer to this thread and very carefully read the instructions towards the bottom of page 1 that tell you how to remove both the fuse panel and the fuse panel backing plate.

The fuses inside that little box are high-amperage fuses, so, even though good troubleshooting technique suggests that “paths of influence” be followed in a logical and sequential order, for sake of safety and convenience, I suggest you actually change the above order of investigation (which is based strictly on paths of influence) so that you carry out the work in the following sequence:

1) Do the battery test with the Midtronics battery analyzer.
2) Before connecting the positive cable back onto the left battery, open the fuse box and investigate the condition of the high-amperage fuses.
3) If there are no problems found with the high amperage fuses, then go to the fuse panel under the steering wheel and investigate the smaller fuses there, as previously explained.

While your car is in the shop (after you have found and rectified the power loss problem), ask the technician to run a diagnostic scan on the vehicle. Check the software version of controller 17. It should read “xx21”, where xx are two numbers that don’t matter (probably 03). If the last two numbers are less than 21, get that controller flash-updated in accordance with the instructions at this thread: http://forums.vwvortex.com/zerothread?id=1878829]Distortion in the Display Unit in the Instrument Cluster (MFI, or Y24) [/url]. Your complaint will be that you are seeing distortion on the small display screen in the instrument cluster.

Check also the letter suffix on the end of the battery controller (controller 71). It should be C or higher. If it is A or B, refer to this post: Electrical Problems (includes TB 27-06-02, RVU, Campaign OH) .

Let me know the outcome of the shop visit.

Michael

[PanEuropean]

Here is a document that explains the fuse assignments in your Phaeton in a little bit more detail than the owner manual does.

Michael

[VWGlf00GL]

Hello Michael!

So I took the car in this morning.. I told and showed the tech what was going on.. For the record, I never had to turn the key to the left, then right for an emergency start. The car has had a "CAN-BUS" problem for sometime now. The car controllers and modules respond (well when they want to). I speculated the "capacitive discharge"; well because we did this previously when the water temp gauge was reading hot, the car was really was fine.

I brought a printout of the directions you gave me (this thread). I showed them to him, he said that he tested the battery a few weeks ago when I was in, and it was fine. No loss of charge. He doesn't like the intermittent responsiveness from the car/controllers.

He tried to plug-in his VAS-5051 tool to 'try' and read/diagnose the car. The car would not respond, as expected. He logged into VW Tech Website (don't recall name). He pulled the wiring diagram for the Phaeton. He pulled fuse #27 under the steering column

(27 - SB27 - Fuse 27 (in fuse holder) 5 A - 285 - Control module with indicator unit in instrument panel insert Data Link Connector (DLC).

It was blown, he changed the fuse, and was able to read the car now! He was able get in there and turn off a few things, and clear the fault codes that he wanted to clear.

Resetting the car allowed the instrument cluster and analog clock to behave properly, no more clock error or frozen tach needle, oil temp, gas, water temp and battery meter. You were spot on with fuse #27, that needed to be replaced! You're really a gem Michael!

I bring the car in next week to complete a small list of things.. I am really happy to have her back and she's herself again. Something so BIG was so small to fix.. Took less than an hour to fix.

Thanks for the battery check/issue, I've printed it out. We're going to change the batteries out in a few months. Regardless of their reading/voltage. I'll have him update the battery controller software suffix when I bring the car back in next week..

Thanks Michael, thank you all!

PS: I met Bryan again (nice to see ya Bryan), one of our 05 Phaeton owners, his car had just over 10,000 miles on it. Still looking clean and smells brand new . We come in pairs at this VW dealership it seems..

Large quote of post above deleted to save space - Michael


Modified by PanEuropean at 1:06 PM 4-10-2009

[PanEuropean]

Quote, originally posted by VWGlf00GL »

...I'll have him update the battery controller software suffix when I bring the car back in next week...

The battery controller cannot be brought up to the required specification with a software update, it has to be physically replaced (see the link I provided to the discussion of the battery controller problem). So, if you have a suffix A or suffix B battery controller, the only fix is "remove and replace".

VW had a Campaign (a recall) out several years ago for this problem. The campaign has since expired, however, your VW dealer may be able to negotiate a bit with VW to see if they will absorb some of the cost of replacing the controller. I think the controller is about a $450 part, it takes about an hour to replace it.

Michael

[VWGlf00GL]

Oh, okay. I thought a software update would work, guess not. I've reviewed your previous post with the battery controller.

No worries. I'll inquire about this next week. Thank you Michael, I appreciate your help here. Your very quick with excellent replies that are spot on, and most of the time a fix for the problem(s) that we have..

Have a great weekend everybody!

- Adrian

[Kcmover]

Michael!

This is why I purchased another Phaeton. It's the friendship and knowledge of you and the rest of the folks on this board.

Larry

Quote, originally posted by VWGlf00GL »

Hello Michael! You were spot on with fuse #27, that needed to be replaced! You're really a gem Michael! Thanks Michael, thank you all! Large quote of post above deleted to save space - Michael Modified by PanEuropean at 1:06 PM 4-10-2009

[PanEuropean]

Quote, originally posted by VWGlf00GL »

Have a great weekend everybody!

Agreed, Happy Easter and Happy Passover to everyone! And, to be all-inclusive, there's only 6 months left until Eid.

Michael