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ECU Relay replacement

Discussion in 'T3 & T4 Tech Help Clinic' started by beerboy, Nov 11, 2019.

  1. beerboy

    beerboy Well-Known Member

    Messages:
    1,005
    Location:
    Sydney
    Not sure if I am going mad here trying to find a new ecu relay. Is it anything special. mine does not have a number on it which seems to be the normal procedure for identifying them.
     
  2. syncro

    syncro Well-Known Member

    Messages:
    9,446
    Location:
    Southern Highlands
    There should be a 9 digit VW number on it. I am not sure but these may be a standard generic relay.
     
  3. Luckyphil

    Luckyphil Well-Known Member

    Messages:
    6,079
    Location:
    Gosford
    The ECU relay is NLA however there is a workaround so you can use a 57 which is the same as the fuel pump relay sitting next to it. I have the workaround procedure at home so will post later this afternoon. A word of warning when removing these relays to disconnect the battery as you can fry your ECU. This is good practice whenever you work on the electrical system.
     
    Grantus likes this.
  4. beerboy

    beerboy Well-Known Member

    Messages:
    1,005
    Location:
    Sydney
    still confused you mean 53 relay? thanks phil and phill. when you get a chance
     
  5. Luckyphil

    Luckyphil Well-Known Member

    Messages:
    6,079
    Location:
    Gosford
    It prob is a 53 for the fuel pump I was running from memory. So this fix will allow you to have both relays the same. In essence what you need to do is change the pin wiring in the plug to work with a 53 just plugging one in will not work. I believe earlier T3's did use 2 of the same relays but for some reason VW change the relay for the ECU to also have a resistor which is what burns out. The function of the van will be the same after the mod.
     
    Grantus likes this.
  6. beerboy

    beerboy Well-Known Member

    Messages:
    1,005
    Location:
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    thanks phil for the clarity :)
     
  7. Luckyphil

    Luckyphil Well-Known Member

    Messages:
    6,079
    Location:
    Gosford
    Wayne murray and Grantus like this.
  8. beerboy

    beerboy Well-Known Member

    Messages:
    1,005
    Location:
    Sydney
    Thanks phil that is a very good document that someone has updated! great wiring diagram. Thats why I am confused then. that relay is a bit of a non starter to start with. will order a couple of 53 relays from brickwerks.

    from the samba

    "The switch to the special 5 pin ECU relay was done to implement the Calif CARB mandated emissions OBD. This mandate was then delayed just before it was to go into effect. So VW switched back to a standard 4 pin ECU relay for the last couple years after 88/89. Of course the last couple years wiring diagrams wrongly still show it, another source of confusion for people trying to resolve tricky problems."
     
    Last edited: Nov 11, 2019

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