# Is the ecu relay 109? Awp dtc help



## xjoegtix (Mar 17, 2007)

I've searched around but it always seems like 109 is talked of being the fuel pump relay and maybe the ecu relay. I have a dtc code and can't figure out where the relay is.


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## atomicblast (Oct 23, 2008)

Under the hood, on the right side, attached the rain tray. It's a little black box. Pop the top.


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## 18T_BT (Sep 15, 2005)

fuel pump relay is 409 and it's under the dash by the OBD2 plug area


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## warranty225cpe (Dec 3, 2008)

I had a hell of a time getting a replacement that worked. Heres the thread I started when I couldnt figure it out. Make sure you get the correct relay. Count the prongs and pay attention to the configuration of the prongs on the new VS old relay. It will save you some headache. And take a quick read of this as well. It should help.

http://forums.vwvortex.com/showthre...tion..(167-or-100-)&highlight=fuel+pump+relay


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## xjoegtix (Mar 17, 2007)

atomicblast said:


> Under the hood, on the right side, attached the rain tray. It's a little black box. Pop the top.


Is this for the ecu relay?


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## xjoegtix (Mar 17, 2007)

warranty225cpe said:


> I had a hell of a time getting a replacement that worked. Heres the thread I started when I couldnt figure it out. Make sure you get the correct relay. Count the prongs and pay attention to the configuration of the prongs on the new VS old relay. It will save you some headache. And take a quick read of this as well. It should help.
> 
> http://forums.vwvortex.com/showthre...tion..(167-or-100-)&highlight=fuel+pump+relay


Thank you for being wicked helpful I really like that you guys responded so fast. I think that I may have confused you with how I worded my question or maybe I'm just confused. I'm getting a dtc code on my dash and I'm not getting any spark. So I looked up why this is happening and everyone said it could be the relay for the ecu. I'm just unsure of where to find the ecu relay.


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## groggory (Apr 21, 2003)

xjoegtix said:


> Thank you for being wicked helpful I really like that you guys responded so fast. I think that I may have confused you with how I worded my question or maybe I'm just confused. I'm getting a dtc code on my dash and I'm not getting any spark. So I looked up why this is happening and everyone said it could be the relay for the ecu. I'm just unsure of where to find the ecu relay.


I'm not 100% sure which relay controls power to the ECU. I know the ECU gets both always-on voltage and switched voltage. The switch voltage obviously comes from a relay.

I also believe the ECU is fused. So go check all your fuses. Easiest way to do this is get your volt meter, set it to dc voltage 20v, put one terminal on a good ground, then go down both sides of each fuse with the car key'd-on and make sure you get ~12V from both sides of every fuse. Takes like 5 minutes.


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## xjoegtix (Mar 17, 2007)

groggory said:


> I'm not 100% sure which relay controls power to the ECU. I know the ECU gets both always-on voltage and switched voltage. The switch voltage obviously comes from a relay.
> 
> I also believe the ECU is fused. So go check all your fuses. Easiest way to do this is get your volt meter, set it to dc voltage 20v, put one terminal on a good ground, then go down both sides of each fuse with the car key'd-on and make sure you get ~12V from both sides of every fuse. Takes like 5 minutes.


Thanks man I already checked all the fuses and they're all good


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## xjoegtix (Mar 17, 2007)

Ecu relay number?


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## warranty225cpe (Dec 3, 2008)

xjoegtix said:


> Ecu relay number?


Im not sure if there is one. A quick googling didnt turn up anything.


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## 18T_BT (Sep 15, 2005)

What is the actual code, otherwise you are chasing your tail. Did you check all the relays and fuses, even the ones under the hood?


http://forums.vwvortex.com/showthre...-of-fuses-for-MKIV-cars-(fuse-too-for-search)


http://uk-mkivs.net/forums/p/489858/3369100.aspx


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## groggory (Apr 21, 2003)

18T_BT said:


> What is the actual code, otherwise you are chasing your tail. Did you check all the relays and fuses, even the ones under the hood?
> 
> 
> http://forums.vwvortex.com/showthre...-of-fuses-for-MKIV-cars-(fuse-too-for-search)
> ...


Fantastic post.

I'm not going to hot link those images in the FAQ, but I'll reference this thread in the FAQ


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## warranty225cpe (Dec 3, 2008)

groggory said:


> Fantastic post.
> 
> I'm not going to hot link those images in the FAQ, but I'll reference this thread in the FAQ


Agreed. Good stuff Val :thumbup:


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## xjoegtix (Mar 17, 2007)

A friend helped me out. Hope it helps you guys


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## xjoegtix (Mar 17, 2007)

Atomicblast thank you too


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## VW_OwneR_85 (Jul 31, 2010)

18T_BT said:


>


Hi guys , the central empty relay socket above 30A is that empty across all mk4 models? thanks


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## shatrabecjou (Feb 6, 2021)

18T_BT said:


> fuel pump relay is 409 and it's under the dash by the OBD2 plug area


is the same for a 2013 vw jetta tdi 2.0?


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