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Jef

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We are amazed at how often stuff like this is skipped over, and even better, people refusing to do this kind of stuff.

We've also gotten a handful of calls about misfire codes, but engine runs fine... so refuse to check compression only to find out later that in fact the cylinder only had maybe 80PSI (5.5BAR). Bet they wish they found that a lot sooner. :banghead:
 
   #3  

Jef

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Caller... another shop did some repairs on a VW, and now the HVAC blower doesn't work. Fuse SC40 is good, but never gets power. A few minutes into the wiring diagram... SC40 passes through the J59 (load reduction relay) and then through SB30. Pops hood and checks fuse box.. SB30 is missing. 7 minutes into the call, "I've been working on this for hours."

Replaced missing SB30 fuse, HVAC blower motor powers up.

ST?ID=86837
 
   #4  

myounus

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I've blown a fuse just thinking about it!
 
   #6  

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Another one... ST?ID=86983

2009 A4, issues with Steering Angle Sensor (G85). The back story, which I found out after the fact, was G85 issue, shop #1 messes with car, then owner of vehicle proceeds to damage parts and shop #2 has vehicle. Shop #2 installed new G85, which is part of the Steering Wheel Electronics (J527). The J527 was dead because prior to shop #2, the customer broke of terminal connector off the J527.

Shop #2 ordered new J527 from dealer. We get it coded and try to do the G85 relearn:

http://wiki.ross-tech.com/wiki/index.php/Audi_A4_(8K)_Steering_Wheel_Electronics

Not getting the "OK" message when doing the Basic Settings 001. Go into MVB 033 and do see live data for the G85. So it sounds like it is right where it started when it went to shop #1. Other codes in car? Yes, ABS and CAN Gateway have no communication with G85 codes.

Hmm... hold on for a minute..... I dig into the wiring diagram for the J527, it has two fuses. So check out fuse SD5 ST1..... and missing. Pop in a 5A fuse, ABS and Gateway codes clear out, G85 Basic Settings now "OK", all warning lights off cluster.

So... a $600 part due to a 10 cent fuse. In fairness, things were a bit confusing and Shop #2 was cleaning up a mess they were handed.
 
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Jef

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Brandon calls about a 2017 Jetta (super poverty spec), no brake lights, no turn signals. J519 has fault code:

03433 BTF-EN-1922 Terminal 30 Back-up light/cornering light: open circuit.

All fuses verified good, twice over. Brakes and turn signals are controlled by the J519 and we poked through the wiring diagram, nothing standing out fuse wise so far... I'm starting to think a bad wire/terminal.

So, for giggles, in fuse box C under dash, any empty fuse spots with 2 terminals? Yes, position 46 has two terminal in it. SC46 is for right side door control modules, J387 and J389. Wiring diagram shows SC46 only goes do those door modules, nothing else. Pops in a 30A fuse, brake and turn signals, J519 code clears right out.

:confused:
 
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Uwe

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So, for giggles, in fuse box C under dash, any empty fuse spots with 2 terminals? Yes, position 46 has two terminal in it. SC46 is for right side door control modules, J387 and J389. Wiring diagram shows SC46 only goes do those door modules, nothing else. Pops in a 30A fuse, brake and turn signals, J519 code clears right out.

:confused:
Somewhere in Mexico, a fuse gnome is laughing his azz off.

-Uwe-
 
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Jef

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Almost forgot to add this one... ST?ID=89139
2011 Jetta, dead, nothing happens with ignition switch. As I understand it, car was towed to repair shop, who then called in a mobile tech, who then contacted me... if terminal /1 is hotwired, car will then power up from ignition switch. /1 of ignition switch comes from fuse SC22...... and blown. Replaced fuse, car powers up as one would expect to now with ignition turned on.
 
   #10  

darkchina811

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Jef said:
So, for giggles, in fuse box C under dash, any empty fuse spots with 2 terminals? Yes, position 46 has two terminal in it. SC46 is for right side door control modules, J387 and J389. Wiring diagram shows SC46 only goes do those door modules, nothing else. Pops in a 30A fuse, brake and turn signals, J519 code clears right out.

:confused:
In my Golf 7 there is a fuse in box C under dash which is supposed to supply power only to external lights. well, if I take it out the instrument cluster also powers off. that is written nowhere.
 
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siLc

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In my Golf 7 there is a fuse in box C under dash which is supposed to supply power only to external lights. well, if I take it out the instrument cluster also powers off. that is written nowhere.
Its pretty apparent in Elsa - fuse SC17 provides battery voltage to the instrument cluster.
 
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darkchina811

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I am talking about SC23 or SC31, which should power the two headlights only. I do not remember specifically what happens, but when I pull one of those, either the cluster goes off or the ignition does not turn on anymore.

car user manual, all schematics, Elsa and all the gods say those two fuses are for the headlights only.

needless to say, this has always happened since the car was stock.

I took another look at the WD and those two fuses go straight to BCM for left/right lights supply. it may be the BCM, maybe the internal wiring allows ignition only when those supplies are present.
 
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   #13  

siLc

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Oh, I see.

Both these are 40A fuses with heavy gauge 4,0mm2 wiring - quite hefty for only running headlights. I'm guessing they are a more general voltage supply for the BCM.
 
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DV52

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I am talking about SC23 or SC31, which should power the two headlights only. I do not remember specifically what happens, but when I pull one of those, either the cluster goes off or the ignition does not turn on anymore.

car user manual, all schematics, Elsa and all the gods say those two fuses are for the headlights only.

needless to say, this has always happened since the car was stock.

I took another look at the WD and those two fuses go straight to BCM for left/right lights supply. it may be the BCM, maybe the internal wiring allows ignition only when those supplies are present.
^^^ From my reading of the WD (which I fully acknowledge could be incorrect) the BCM on the mk7 has 6 x separately fused T30 supply points. SC23 (pin#66A) and SC31 (pin #1C) are indeed for the right and left headlight Leuchte-sets (I believe). SC42 (pin #73A) is used by the BCM for the central locking function which leaves 3 x "general" T30 supplies:SC43 (pin #73C), SC4 (pin #4C) and SC26 (pin #1A).

The BCM also produces (or, rather appears to produce) 4 x T15 supplies which I assume are generated through one, or more of the "general" T30 fuses: pin #13A for the main T15 voltage supply relay (J329), pin#14A for the dash panel wiring harness (T15a) and the two Ignition/Starter switch (-D-) connections on pin #44A and pin #47A (although I'm not sure whether these latter 2 x supplies come from, or to the module @ hex 44)

But if anyone knows how the supply from the "general" T30 pins are distributed - I'm all ears!!!

Don

EDIT: For those that have an interest - here is a picture of the PCB from a BCM for MQB platform vehicle - it's quite a sophisticated control processor!!

 
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   #16  

Jef

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2006 A3, EPC light on.

P2294 008852 VCDS-EN-190211 Fuel Pressure Regulator Valve (N276): Open Circuit

Replaced both low and high side fuel pressure sensors, pulled HPFP out and visually inspected, but no issues found... replace HPFP.

OK... so check fuse SB6. And fuse is missing. Popped in a 15A fuse, code finally clears out.
 
   #17  

Jef

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2006 A3, front and rear wipers not working, front and rear washers dead as well. Seems we get the call after the J527 and J519 have been replaced.

J527, look at MVB data, can see wiper/washer switch conditions happening as per factory design with operated. No issue found.

Are there any fault codes in the J519? Yes, and this is when I'm told the J519 was swapped and find out it hasn't had soft coding done. Good news, an Auto-Scan was performed prior to any parts swapping, so we went to the /scans folder, found the original Auto-Scan, copy/paste the J519 coding. Still no wipers, call ends due to customers at shop.

Following day, now some relays on the J519 have been replaced, no changes. So what codes are in the J519?

Has a couple of open/short to ground codes for "control circuit" of the washer pump and wipers. So fuse SB52 any good?

... and a missing fuse. Popped in a fuse, wipers work like a champ!
 
   #18  

Jef

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2008 R32

P0491 001169 VCDS-EN-190211 Secondary Air Injection System: Bank 1: Insufficient Flow
P0492 001170 VCDS-EN-190211 Secondary Air Injection System: Bank 2: Insufficient Flow

Tech notes that the sec air pump never runs. Walked through output testing and J299 Sec Air Inj Pump Relay, can hear it clicking, but no action from the pump.

Fuse SB51 condition?



Pop in a 40A fuse, run output test again, now the air pump is running.
 
   #19  

Jef

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No comm with car. Using a HEX-USB+CAN (HEX+CAN), port test comes up as not plugged up to car. Is the LED on the HEX+CAN powered up? Nope. Plug up to any other car, does the LED power up? Yes.

Fuse SC23 good? No, it is popped. Replaced bad fused, can communicate with car now.
 
   #20  

Jef

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2007 Eos, top won't work, stuck open/stored. Trunk lid can be open and closed, but takes a lot of effort to close it (latch). 26-08-002 data is spot on for an open/stored top. Tech did note the trunk lid close assist (striker on body) doesn't raise up when trunk is opened, that is why it is hard to close rear lid. Tech replaced that motor/striker for closing assist with new unit from dealer, no change.

No codes in CCM. J256 Roof Electronics has 1 code: 02805 - System Interference

The rear lid close assist is operated by the J256 on the Eos. Wiring diagram has it listed as J657 "Door closing assist control module"... :banghead: Anyway, it ain't working. Fuse SC19 good?

... there is no fuse SC19... .. uh.. yeah... there are 2 electrical contacts in there....
Pop in a 7.5A fuse, clear codes... and now everything is working just fine. Car was at another shop and AFTER that visit, the issues started. No clue what other shop did beyond pull a fuse out. :confused:

I'll admit, the fault code of 02805 is typically goof up of the mechanics on the top, so it stops operation of top due to confusing (conflicting) data. It would of been WAY better if there was a fault code along the lines of "closing assist module: No Communication". But at the same time, if an electrical item ain't working... and it is fused....
 
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