2012 Golf TDI - No Dash, No Crank, No Horn, No Comm

[marty_seguin]

Hi-

I'm new to VWs but I'm an experienced auto tech. I did some work on my friend's 2012 Golf TDI that involved disconnecting the battery and rocking the engine around.

After the work was completed, I reconnected the battery and went to start the car - nothing! Start button does NOTHING, dash does not light up. Battery is fully charged and connections are good, high beams are bright. Also, the horn does not work. All fuses in both boxes have continuity and look fine.

There is power at the OBD port, but VCDS will not communicate with any modules during an auto-scan.

I suspect the BCM (J519) has failed somehow since all of these things that don't work get power through it. I'm going to try replacing that, but even if it solves the major problems I understand that I will have to re-code it somehow. Is there any way to get the values off the old BCM?

Also open to other diagnosis ideas - I'm kind of at a dead end. I appreciate any help you guys can give.


Thanks!

 

[Dr Sheldon]

I'm going to try replacing that,

Do NOT do that - Not until you have evidence it is faulty !!

Can you post an Autoscan ??

There is power at the OBD port, but VCDS will not communicate with any modules during an auto-scan.

Can you communicate with J533 Can Gateway ?

 

[davisev5225]

Press and hold the brake, turn on the hazards, and turn on the high beams. You should now be able to communicate with any modules that are part of the immobilizer. Please run an auto scan in that state and post the results.

(This is how dealers and locksmiths can program a replacement key when you don't have any working keys to turn the ignition on with.)

 

[marty_seguin]

It appears that I cannot communicate with the gateway.

I tried the brake/hazard/high beam and that did not change anything.

Scan: Auto-detect
Function not supported by the gateway.
End--(Elapsed Time: 00:02, VBat Start/End: 12.5V


"Gateway does not respond"

 

[davisev5225]

A dead gateway would explain why you can't turn the ignition on...

 

[JMR]

I would unplug and replug the gateway. Also..if the car has parking assist module , please try and unplug that and see if the car comes to life

 

[Dr Sheldon]

I tried the brake/hazard/high beam and that did not change anything.

Did you try that with your two middle fingers crossed on your left hand hidden up your Skirt, tongue tickling the hairs on your nose ?? Or does this have a DPF and Spark Plugs ?

 

[marty_seguin]

I’m not sure how to post an autoscan when it won’t autoscan.

I’ll locate and check on the gateway when I get home - I just learned that part exists

 

[davisev5225]

Did you try that with your two middle fingers crossed on your left hand hidden up your Skirt, tongue tickling the hairs on your nose ??

No need to be snide, this is the official procedure to "wake up" the gateway and related immobilizer modules when you don't have a working key/fob. You should know that with all your years of experience...

 

[Dr Sheldon]

No need to be snide, this is the official procedure to "wake up" the gateway and related immobilizer modules when you don't have a working key/fob.

I'm for sure not snide - Can you define Snide ??

With respect my friend ! Getting the car to accept a door opening command is a pole apart from Unlocking the Immobiliser!!

After the work was completed, I reconnected the battery and went to start the car - nothing! Start button does NOTHING, dash does not light up. Battery is fully charged and connections are good, high beams are bright. Also, the horn does not work. All fuses in both boxes have continuity and look fine.

QUESTION :Are you @davisev5225 suggesting that @marty_seguin has achieved all that whilst locked out of the car ?? Through a Broken Window ?

 

[marty_seguin]

I did fail to mention that the key fob does still work. Doors lock/unlock, horn chirps, etc.

 

[Dr Sheldon]

You should know that with all your years of experience...

FFS-This is a support forum ? Not a platform for you to Evaluate / Compare your skills and knowledge to any other contributor !?

Stay on board and do not please take criticism as a negative - It is education that you can utilise the very next day - Given that you have the minerals to do so !!

 

[Dr Sheldon]

I did fail to mention that the key fob does still work. Doors lock/unlock, horn chirps, etc.

@davisev5225 - The Irony

 

[Dr Sheldon]

I did some work on my friend's 2012 Golf TDI that involved disconnecting the battery and rocking the engine around.

Clutch - Gearbox - Belt - What ?? Is it a secret ?

 

[marty_seguin]

I replaced the DPF with a less-restrictive exhaust pipe per the vehicle owner’s request. Not something I’d do to my own vehicle, but seemed simple enough mechanically. I wasn’t expecting to get deep into electrical diagnosis with this job

 

[davisev5225]

@davisev5225 - The Irony - You P35t !!

The BCM (Central Convenience or Central Electric, most likely) accepting keyfob commands to unlock the doors is not the same thing as the network of modules that form the immobilizer system being online and allowing the ignition to power on.

Once again, you're not helping here. There's clearly an electrical issue with one or more of the modules that are part of the immobilizer, most likely the CAN Gateway, so that is what needs to be addressed. Instead, you're chasing after unrelated engine modifications.

 

[marty_seguin]

Okay, I finally found and removed the gateway. It was really up in that dash.

PN 7N0 907 530M

I have no idea how to test it - I'm thinking I'll just order a known good one off eBay instead of $275 for a new one. There are also Chinese versions on Amazon...thoughts?

 

[davisev5225]

I have no idea how to test it - I'm thinking I'll just order a known good one off eBay instead of $275 for a new one. There are also Chinese versions on Amazon...thoughts?

1. Do not buy aftermarket control modules, especially ones that are C.R.A.P !
2. Do not replace your existing module until you perform some basic diagnostic tests.

The best course of action from here is to get the wiring diagram <--- (clickable link) for your car and figure out where power, ground, and comms are. Verify you can get power and ground at the module connector, then load test it using a 12V incandescent light bulb. If that's all good, move on to the data lines. Verify continuity from the connector off to wherever they go.

If all of that checks out, and after plugging the module back in you still get no life out of it, then you might consider a replacement.

Also, your car is old enough you might find it in local junkyards. Might be worth shopping around to see if you can find a used one to swap in. Coding, adaptions, etc. might be an issue since you don't have an existing scan to work from, but getting the hardware (if it indeed died...) is where you have to start.

 

[Automecatrnicag]

es muy común que falle ese módulo de la dana deja de haber comunicanion entre los módulos todos estos vw modelos 2006 en adelante

 

[Dr Sheldon]

I replaced the DPF with a less-restrictive exhaust pipe per the vehicle owner’s request.

You are in whole new world of Pain now !! Is the ECU aware that the DPF has gone ??