# Wiring Guru Help! Power Supply Relay for ECU (J271 or J363)



## un1ko (Apr 6, 2004)

This has been an ongoing issue and I've posted other post about the different issues. I think I have to figure this issue prior to my other ones. 

The twist with this issue is that I'm putting an AWM wiring harness into a B5 S4 chassis APB. I've been able to keep most of the electrical connections OEM, but A4 and S4 ECU's receives power on different pins on the orange chassis connector in the ECU box. That's why I'm getting this error. 


17925 - Power Supply Relay for ECU (J271 or J363) 


I also discovered that this is affecting issues with flashing my ECU with the Maestro, it's times out. 


I guess my question is... Can bypass this relay or do I need to resolve this? I do need to continue flashing my ECU of course. 

This is AWM 1.8T




















This is APB 2.7T






















I'm thinking out loud.

With the N205 (cam adjustment valve) - I wonder if I can connect it to T6at/3? - because the APB the N205 goes to the G108 Heated o2 sensor. AWM does not have it. Both have G39 which is the heated o2 sensor for AWM and APB has it too. Also since the APB does not have S204 fuse. 

For pin 121 - I should be ok - both connect to T10ar/1 - ECU Pin 21 is the ground trigger for the relay. The Relay's 12V+ output drives 2 fuses: 1 for the VVT (if equipped), and 1 for the ignition coil packs (fuse #29). The power line to the coil packs is also connected to ECU pin 121 << This is how it monitors the operation of that relay, and thus throws that code for it


For pin 21 - Is the confusing part. I got this information, but how can I fix this? Per the information I gathered, pin #21 is definitely a is a ground trigger, AND it needs to see 12V. With this issue what happens on the me7.5 when that pin isn't powered? No communication with my flashing software as I mentioned before.

Something worth noting: The b5s4 doesn't need this wire powered, nor does the 2.7t a6 that came equipped with me7.1. Me7.1.1 and later require it. IIRC, it gets powered via relay 429 (when installed in the car)

I also just found this. Audi_ECU_J271



Also dumb question. Where do I find this? Anyone have a pic?













Any help would be great. I feel like I'm getting so close. Thanks in advance for anyone that can help!!


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## Chris164935 (Jan 10, 2004)

Hmmm... I want to say that something is missing on your wiring harness. N205 is the solenoid that adjusts the camshaft tensioner on the back of the head (VVT). The connector should be a part of your AWM engine harness. If you have a 100% complete engine harness, I believe the only things you should be worried about are the connectors from the body that go to the engine harness (these connectors go to the instrument cluster and a couple other non-engine related items... Maybe ABS, Airbag module, A/C control, etc.) Everything else should be there on your AWM harness (J271, N205, etc).
As I type this, I am starting to think more and more that maybe your harness is not complete. That 3-way carrier you posted at the bottom is found in the same plenum as the AWM ECM itself. It sits right next to it. 3 is the ECM Power Supply Relay (J271),5 is the fuse for camshaft adjustment, and 7 is the fuse for secondary air pump. If your harness is not installed in the car currently, I believe that each part of the carrier is it's own little box/connector; they aren't attached to each other, and they mount individually into the ECM plenum.
Not sure if this is from an AWM setup, but this picture will give you an idea of where the 3-way carrier is located (or should be located).


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## un1ko (Apr 6, 2004)

Chris164935 said:


> Hmmm... I want to say that something is missing on your wiring harness. N205 is the solenoid that adjusts the camshaft tensioner on the back of the head (VVT). The connector should be a part of your AWM engine harness. If you have a 100% complete engine harness, I believe the only things you should be worried about are the connectors from the body that go to the engine harness (these connectors go to the instrument cluster and a couple other non-engine related items... Maybe ABS, Airbag module, A/C control, etc.) Everything else should be there on your AWM harness (J271, N205, etc).
> As I type this, I am starting to think more and more that maybe your harness is not complete. That 3-way carrier you posted at the bottom is found in the same plenum as the AWM ECM itself. It sits right next to it. 3 is the ECM Power Supply Relay (J271),5 is the fuse for camshaft adjustment, and 7 is the fuse for secondary air pump. If your harness is not installed in the car currently, I believe that each part of the carrier is it's own little box/connector; they aren't attached to each other, and they mount individually into the ECM plenum.
> Not sure if this is from an AWM setup, but this picture will give you an idea of where the 3-way carrier is located (or should be located).


Ohh.. ok now it make sense. I do have it in the AWM wiring harness, what confused me was that it's saying that the S4 has it too just not all the relays. So I thought it was under the dash. I don't have VVT I'm using an AEB head and I'm canceling it with the Maestro. Maybe later I'll add it since I read that you can get more hp with VVT on. 

I thought 205 has to do with the cam sensor in front of the cylinder head. I went back to the wiring diagram to figure out how I can still get the connection to work, since I need to get pin 21 to function in order to flash my ECU. 

I have to understand how J271 works - I feel that T10m/4 goes to pin 62 to the ECU and pin 1&2 from J217 which seems to be fine. Then T10ar/1 goes to Fuse 29 and back to pin 6 from relay J271, but 205 I feel like I can maybe connect it to T10ar/8 (D23)

After writing all this I'm confused I have to come a little later.

AWM









APB


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## Chris164935 (Jan 10, 2004)

The thing is, if you have a genuine AWM wiring harness, you should not have to do any wiring work to properly have the J271 module running. Unless you are using an S4 ECM...
You either have the wrong harness, a butchered harness, or your harness needs repair. I'd recommend finding another AWM harness from a 2001 A4 or Passat. If possible, make sure that it comes with the J271 module and other fuses. I'm not sure of any methods to test the functionality of the J271 module itself. With another harness, you will at least find out if your wiring was bad or the module was bad.


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## Chris164935 (Jan 10, 2004)

Also, forgot to mention, even with the VVT solenoid unplugged, you would not get any DTCs for J271, just open circuit for N205.


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## un1ko (Apr 6, 2004)

Chris164935 said:


> The thing is, if you have a genuine AWM wiring harness, you should not have to do any wiring work to properly have the J271 module running. Unless you are using an S4 ECM...
> You either have the wrong harness, a butchered harness, or your harness needs repair. I'd recommend finding another AWM harness from a 2001 A4 or Passat. If possible, make sure that it comes with the J271 module and other fuses. I'm not sure of any methods to test the functionality of the J271 module itself. With another harness, you will at least find out if your wiring was bad or the module was bad.





Chris164935 said:


> Also, forgot to mention, even with the VVT solenoid unplugged, you would not get any DTCs for J271, just open circuit for N205.


I have 3 AWM wiring harnesses, I tried all 3 and all of them had the same issue. I was working a little on it an pin 21 is not getting 12v all the other connections seem ok. I wonder if I can bridge it from pin 1 from the relay?


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## Chris164935 (Jan 10, 2004)

Is the harness connected to the instrument cluster? What cluster are you using? I saw in another thread that you had a DTC for no communication between the ECM and the instrument cluster. Maybe check the connector T3aa (it is mentioned in the first wiring diagram you posted) as well as fuse S229. Don't worry about the S4 wiring diagrams as they won't help you. The issue your are having is related to the AWM wiring diagrams.
Other than that, the only time I've seen this issue before was from an improperly flashed ECM. My ECM was supposedly bench flashed. When i installed it and tried to crank the car it would start for a second and then die (similar to when the immobilizer kicks in, but my car doesn't have that). Scanned the car and had a similar J271-related DTC. After we went as far as to purchase and install a brand new J271, turns out after the ECM was flashed back to stock, everything was fine again. Do you have access to a bench flasher or anything that would allow you to flash your ECM without any issues?


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## un1ko (Apr 6, 2004)

Chris164935 said:


> Is the harness connected to the instrument cluster? What cluster are you using? I saw in another thread that you had a DTC for no communication between the ECM and the instrument cluster. Maybe check the connector T3aa (it is mentioned in the first wiring diagram you posted) as well as fuse S229. Don't worry about the S4 wiring diagrams as they won't help you. The issue your are having is related to the AWM wiring diagrams.
> Other than that, the only time I've seen this issue before was from an improperly flashed ECM. My ECM was supposedly bench flashed. When i installed it and tried to crank the car it would start for a second and then die (similar to when the immobilizer kicks in, but my car doesn't have that). Scanned the car and had a similar J271-related DTC. After we went as far as to purchase and install a brand new J271, turns out after the ECM was flashed back to stock, everything was fine again. Do you have access to a bench flasher or anything that would allow you to flash your ECM without any issues?


I have both AWM and S4 cluster, but right now I'm using the AWM. Based on Eurodyne that's the only way I can flash my ECU. Ok so at first this week kind of sucked because I had to change the brakes on my wife's Touareg, then run errands. So today I got up early to work on my car and it paid off. It's 95% fixed!

I cut the T3aa/2 wire and bridged it to T10ar/1 and it worked! I was able to run the throttle body alignment, flash my ECU and I drove around the block, check engine light is off. Now the only issue I have is that the fuel pump doesn't turn off, I have to disconnect the negative from the battery and it's fine. So I have some homework to do. 

After that I have to connect the electric fan and two oil leaks that I see. I'm pretty excited! I know I have to run some logs, but the car is not pushing the way I thought it would. I'm going to check my boost control and see how much boost I'm pushing.


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## Chris164935 (Jan 10, 2004)

Cool. So, at least now you know the issue is with the wiring from the instrument cluster to connector A151. Does the instrument cluster work with how you have it wired now?

As for the fuel pump, is this an aftermarket pump that you wired up?


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## un1ko (Apr 6, 2004)

Chris164935 said:


> Cool. So, at least now you know the issue is with the wiring from the instrument cluster to connector A151. Does the instrument cluster work with how you have it wired now?
> 
> As for the fuel pump, is this an aftermarket pump that you wired up?



Yeah the cluster works, but I don't know if it's working a 100%. I'll have to do a full scan on the vag-com and see if any errors come out. As for the wiring I have the AWM dash wiring harness, so I'm going to trace T3aa/2 and see where it goes and from there go to my S4 and copy the it. Maybe I should of done that from the beginning. Today I'll try to work on it a little.

I do have an aftermarket pump, but I wired it like the OEM was.


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