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Author Topic: Med9 passat 3.6 bws no communication  (Read 5095 times)
tahz
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« on: January 11, 2023, 12:33:16 PM »

Good day

I have done a swop into my mk4 with a 3.6 bws

I have used kess and done an immo off

Vehicle starts and drives

The can is communicating with the cluster as it shows the rpm

But I am unable to read it with vcds - just says no communication

The wiring harness from the Passat does not have a k-line wire
I have added one in and still no communication

Also when tested the k-line reads 12v - not sure if it’s correct

I read the ecu with vcds before removing it from the Passat
And harness and ecu came from the same vehicle

could someone please help with some guidance

Do I need a can gateway from a Passat to communicate or should vcds beable to pick it up
And is the added k-line suppose to read ?
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_nameless
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« Reply #1 on: January 11, 2023, 12:44:58 PM »

Good day

I have done a swop into my mk4 with a 3.6 bws

I have used kess and done an immo off

Vehicle starts and drives

The can is communicating with the cluster as it shows the rpm

But I am unable to read it with vcds - just says no communication

The wiring harness from the Passat does not have a k-line wire
I have added one in and still no communication

Also when tested the k-line reads 12v - not sure if it’s correct

I read the ecu with vcds before removing it from the Passat
And harness and ecu came from the same vehicle

could someone please help with some guidance

Do I need a can gateway from a Passat to communicate or should vcds beable to pick it up
And is the added k-line suppose to read ?
you need can h and can l to the port.
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gremlin
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« Reply #2 on: January 11, 2023, 12:57:21 PM »

The wiring harness from the Passat does not have a k-line wire
I have added one in and still no communication

Also when tested the k-line reads 12v - not sure if it’s correct

This ecu doesn't have diagnose over K-line.
It use CAN bus.
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tahz
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« Reply #3 on: January 12, 2023, 01:05:10 AM »

This ecu doesn't have diagnose over K-line.
It use CAN bus.

Thank you for confirming this
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tahz
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« Reply #4 on: January 12, 2023, 01:13:30 AM »

you need can h and can l to the port.

It is currently connected to where the previous ecu can h and can l was connected
The cluster is seeing signal from the ecu

In theory if I connect the can h and can l direct to the obd2 port it should read ?
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prj
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« Reply #5 on: January 12, 2023, 03:42:48 AM »

Yes, it will work.

On a Mk4 golf there is no CAN at all in the OBD socket, only the K-Line.
So you need to connect CAN H and CAN L also into the OBD socket.
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_nameless
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« Reply #6 on: January 12, 2023, 09:24:02 AM »

Yes, it will work.

On a Mk4 golf there is no CAN at all in the OBD socket, only the K-Line.
So you need to connect CAN H and CAN L also into the OBD socket.
M3.8.3 may not have can at the port but me7 surly does. At least here in the states, I use a obd port that I've cut out of a junk car to make a bench flash setup, so I can confirm this.
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prj
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« Reply #7 on: January 12, 2023, 12:41:40 PM »

M3.8.3 may not have can at the port but me7 surly does. At least here in the states, I use a obd port that I've cut out of a junk car to make a bench flash setup, so I can confirm this.
Are you sure that it is PTCAN?

I've not looked at the schematics. But IIRC the only connection to ECU on these is through the cluster, first K-Line then W-Line.
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terok
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« Reply #8 on: January 13, 2023, 01:39:41 AM »

CAN wires from diag port only go to gateway (cluster).
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tahz
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« Reply #9 on: January 13, 2023, 08:50:43 AM »

Yes, it will work.

On a Mk4 golf there is no CAN at all in the OBD socket, only the K-Line.
So you need to connect CAN H and CAN L also into the OBD socket.

I seen the can h and can l wires connected to the obd port and thought it would be
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tahz
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« Reply #10 on: January 13, 2023, 08:53:36 AM »

M3.8.3 may not have can at the port but me7 surly does. At least here in the states, I use a obd port that I've cut out of a junk car to make a bench flash setup, so I can confirm this.


This car was originally a 2.8 4motion

So it had those wires
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tahz
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« Reply #11 on: January 13, 2023, 08:56:16 AM »

CAN wires from diag port only go to gateway (cluster).

Thank you

Will be trying to connect the can h and can l directly to the port
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tahz
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« Reply #12 on: January 13, 2023, 10:11:36 AM »

Connected directly to the port and reading perfectly

Thank you so much for all the assistance and knowledge
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prj
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« Reply #13 on: January 13, 2023, 12:27:12 PM »

Yeah gateway won't pass anything to the ECU on these, because all the ECU diags are K-Line.
I have experience only with the older M3.8 stuff and I am pretty sure there were no CAN pins in that connector.

Well, OP did not say what year the Mk4 is... so how can I know...
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tahz
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« Reply #14 on: January 13, 2023, 09:24:40 PM »

Yeah gateway won't pass anything to the ECU on these, because all the ECU diags are K-Line.
I have experience only with the older M3.8 stuff and I am pretty sure there were no CAN pins in that connector.

Well, OP did not say what year the Mk4 is... so how can I know...

You are right the me3.8 ecu/ car does not have the can goodies

My apologies for not mentioning which mk4 it was

Been out of it for awhile and was looking for the info so I don’t unessarily burn anything on my car

Thank you again to all it was very useful

Figured out the immo delete and vehicle starts and drives

Now to figure out the rest of the deletes
Thanks again
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