ABF - temperature sensor (G62) wiring

Discussion in '16-valve' started by okops, Dec 7, 2019.

  1. okops New Member

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    Hello,

    could you please advise how should be the temperature sensor (G62) connected?
    Does it go directly to the ECU?
    Should it be connected to PIN 14?

    My ABF was swapped (5 years ago in Audi B4) and I doubt that something with the wiring is messed up based on what I saw today in VCDS (check the values in the video below).
    3 sensors were already changed after they died (lifespan below 1 year).
    What I see is that the temperature is too high and the values jump from 94 to 97 degrees and then suddenly up to 120 degrees for example.
    The engine is not overheating definitely and in addition its performance is not good, especially when it reaches the temperature of 90 degrees (based on the info from the gauge).




    Best Regards.
     
  2. 2swe Forum Member

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  3. rubjonny

    rubjonny Administrator Staff Member Admin

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    jumping up to 120 would suggest either the sensor is bad internally or you have an intermittent short on the signal wire to ground.

    all of the engine sensor brown/white wires tap together into a wire which then goes thru the round plug back to ecu pin 33, I would suggest you pull the loom off the engine back to the round plug then split all the tape off on the bench. usually you'll find its all cracked round the back of the head from exhaust heat
     
    Last edited: Dec 10, 2019
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  4. 2swe Forum Member

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    did you try to measure the temp sensor resistance ? it should be steady at constant temperature. if it is not, then the sensor is faulty..
     
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  5. okops New Member

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    I will perform these checks, I also believe that something is wrong with the wire to the ground.

    The resistance of the sensor (brand new) was tested before and was ok.
     
  6. rubjonny

    rubjonny Administrator Staff Member Admin

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    just to add if you try to test between the sensor ground pin and the chassis you wont see continuity, you need to test between sensor and ecu pin 33 :)
     
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  7. okops New Member

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    Some update:
    The wiring was checked and no problems were found.
    According to the guy the temp sensor is faulty or maybe something with the ECU is wrong (I got another one so I will install it).
    I will first buy another G62 sensor, hopefully this will solve the problem.
     
  8. okops New Member

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    Also could you please confirm if the temperature sensor is number 7 from the picture below - the part number should be
    026 906 161 ?

    [​IMG]
     
  9. rubjonny

    rubjonny Administrator Staff Member Admin

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    yes thats the one, its screwed into the side of the head in the bottom left hole if you're looking at the engine side on
     
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  10. okops New Member

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    Hello,

    I changed the temperature sensor but still the values are jumping up to 120 degrees.
    Then I installed another ECU but there was no improvement.
    So it is sure that I should check the wires by myself.
    Most likely I will re run a new wire from the sensor pin back to PIN 33 on the ECU.
    Before I do that I want to measure the volts - should I get 5 volts on both pins related to the temperature sensor?

    Best Regards.
     
    Last edited: Jan 6, 2020
  11. rubjonny

    rubjonny Administrator Staff Member Admin

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    yes thats right, 5v across the temp sensor pins :)
     
  12. okops New Member

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    Hello,

    The weather got better so I had the chance to remove the tape and check the wires.
    One of the G62 wires is related to the block instead of going to the round plug and then to pin 33.
    Most likely this is where the problem with the bad engine performance is coming from...
    [​IMG]
     
  13. rubjonny

    rubjonny Administrator Staff Member Admin

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    wiring looks a little stiff and split, best to remove the whole sensor loom from the engine and fully strip down and repair. its probably much worse round the back where it runs above the exhaust
     

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