CAN Gateway Issues

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ajh
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Joined: Sat Apr 24, 2021 5:11 pm
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CAN Gateway Issues

Post by ajh »

Hiya.

This post is more for someone else. My brother is looking at their car. I'm in the VAG family, but not a Polo owner, so don't know my way around them in terms of common faults. This is more of sometihng on the fly I'm dealing with.

It's a VW Polo (9N3) as much as I know. Has an Interior Light that doesn't go out and an Airbag Light lit up.

I talked my brother through connecting with VCDS on Auto Scan, but it's not picking up any modules except for 01-Engine and 46-Central Convenience (J393), I think.
If you try to connect manually to any module except listed, you just get the "No response from controller" message in VCDS.

I've had him to a test on the cable, and K1/K2 aren't showing as shorted. My first thought is that there's a problem with the CAN Gateway/BCM as you can't even connect into it. Other than that, I'm assuming there's an issue with a Fuse, CAN Wire, Ground, or Cluster Perhaps.

I don't have the wiring diagrams for the car, so basically working blind. I'm reading through the training manuals from VW, and it seems that the CAN Gateway (J533) is sometimes built into the BCM (J519)

Any suggestions of things worth checking quickly. Other than the basics of checking the voltages / resistance of the CAN wires, and making sure the Cluster is OK. I'm a bit stumped currently. Not sure if Polo have the stupid water ingress issues anywhere which affect Electrics, or have known issues with bad grounds or failed Gateways.

I'm assuming the ECU and J393 are wired differently. Communication is established through the Databus connector, so seems to be pointing to Gateway/Controller issues currently.

The cable I'm using is the HEX+CAN, so it should be capable of scanning the vehicle as it supports up to 2015 IIRC.

Treat me like I'm stupid, I'm happy with my own vehicle but only know the basics with others in the range.

Thankoos
ajh
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Posts: 2
Joined: Sat Apr 24, 2021 5:11 pm
Drives: Audi A3
Location: Durham
Contact:

Re: CAN Gateway Issues

Post by ajh »

Been making some more notes this morning so I have a clearer head. Was a bit tired yesterday.

I imagine all the CAN network signals are going through either the cluster or the BCM. I'm going to do some basic resistance and voltage checks on the diagnostic port. As I think it's wiring issue at the moment.

I don't have a scope to check that side of things out, so there's only so much I can do. Possibly auto electrici jobbie, but given how s**t VAG electrics are is I wouldn't be surprised if it's wiring
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