VR6 ECU wiring connections - Corrado

Discussion in 'Electrical' started by Mk1Stevey, Jun 26, 2019.

  1. Mk1Stevey New Member

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    Hi all, been using this site for years and always found my answers, but this time I can't find the answers I need so wondered if someone can help.

    Problem is my earth trigger isn't switching on for my fuel pump relay (pin 85 - or slot number 3) . This is what's stopping my pump to prime.

    So I've found out that on the ECU I have earth outs on the multipin connector at pins 1, 7 and 56. Can someone tell me where these are earthing at so I can check them, and make sure they are good.

    Anything else I can check. I'm going to check continuity between relay pin 85 and pin 6 on ECU plug, is this a direct cable or does it have a connection block in it?

    Other things I'm going to check is permanent and ignition power to ECU (pins 23 and 54) . Apart from ECU being dead is there anything it could be or I need to check.

    Car is a OBD1 VR6 Corrado
     
  2. rubjonny

    rubjonny Administrator Staff Member Admin

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    Hello there :)

    First off slot 3 on a corrado is for the ECU relay 109, the earth for it is fed from pin 9 on the ECU to G1/7 on the fusebox. Fuel relay is 67/80/167 in slot 12, and earth for this is fed from ECU pin 6 to G1/3.

    If the ECU wont trigger the 109 relay check you have ignition live to pin 38 this is tapped to the coil live from G1/4 on the fusebox. Also look at the earths, main earth are on 1 & 55. 7, 56 and sometimes 10 are common earth for the ECU sensors

    Pin 23 is power output from the ECU relay, and pin 54 is your permanent live to Y spade or G2/9 :)

    if you unplug the ECU and switch the ignition on, if you earth pin 6 the fuel pump should run and if you earth pin 9 the ECU relay should click and you'll then get power to engine electrics, ECU pin 23, MAF power, fuel injectors etc.
     
  3. Mk1Stevey New Member

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    Great thanks it solved all my problems!!
     
  4. Mk1Stevey New Member

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    Hi Jonny. Thanks so much, so I fixed that problem

    You seem to be a bit of a wiring genius so have another question since I got the car running after 5 years sitting I took it for a drive and if I go over 10mph I get an abs light. This then goes off after switch off and when you restart all is fine and self tests with no problems, but again go for a drive and it clicks on.

    I've done vagcom on it and it gives code 01276 16/00 abs pump - signal not in tolerance. I've checked fuses, and both under dash are good, I've swapped ECU and no difference, but have an issue with the relay I think. Number 79 under dash clicks on, then I have 2 numbered 179 neither of these click, 1 has a 30a fuse under the other doesn't.

    Can you give me any pointers?? Should they click with ignition on like number 79 next to them?

    Hope you can help!!
     
    Last edited: Jun 29, 2019
  5. H8V

    h8v Forum Member

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    Given that it all checks out when stationary, but only indicates a fault when moving, then check the sensor heads are clear of debris, and that the gap to the reluctor rings is OK. Also that the reluctor rings are clean and in good condition. Corroded and/or split reluctor rings are quite a common problem.
     
  6. Mk1Stevey New Member

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    Thanks for the reply, would that not throw a sensor fault code as opposed to the pump though?? Or as the sensors have the correct impedance across them the computer doesn't see it as them faulty??
     
  7. H8V

    h8v Forum Member

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    I was working with the fact that the ABS self check does not detect any fault when stationary, but only when the car starts to move. Only when moving does the ABS sense there is a fault, presumably because the signals from the wheels do not match.

    When stationary the only sensor check that can be made is to measure the impedence. When moving it can check the signals. In any case, the ABS does not operate at very low speeds, under around 10mph. I think this may be why a fault is only indicated above that speed.

    I located an ABS fault on an old Saab by measuring the resistance of each sensor to check for continuity, and then by measuring the voltage generated across each sensor while rotating the wheel. You can do all this from the ABS computer plug if you can find the circuit diagram for your unit.

    Googling the fault code gives these:

    Is this any help?...http://www.golfgtiforum.co.uk/index.php?topic=211776.0 (sorry the pics don't work)

    or this...https://www.clubpolo.co.uk/topic/312683-6n2-abs-error-01276-abs-hydraulic-pump-v64/

    or this...https://uk-polos.net/viewtopic.php?f=10&t=58585
     
    Last edited: Jun 30, 2019
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  8. Mk1Stevey New Member

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    I'll check the sensors then as resistances are all good on sensors but maybe bad when rotating I guess.

    If it is the pump then that can wait till I have more time.
     
  9. H8V

    h8v Forum Member

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    I think the sensors should be something like 1K ohms each, or all a similar reading at least, but it's possible that there is a faulty connection on the ABS computer circuit board.

    See what RJ says. He knows more about these cars than is good for any normal person!
     
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  10. rubjonny

    rubjonny Administrator Staff Member Admin

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    Good points above and are where I would start for sure. The ABS units can fail, if you've seen the wheeler dealers corrado episode he has to take the unit to a specialist for repair. If not, why not :lol:

    All of my corrado ABS diagrams only reference 2 ABS relays so I wonder if you have a 2nd 179 relay where you shouldn't, check the wire colours on the relay sockets. Both ABS relay sockets should have inline fuse on top with a fat red wire to the battery live terminal so you can easily ID them
     

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