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Audi A4 1.9 TDi - Temperature Guage

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by Deanjames, Feb 6, 2013.

  1. Deanjames
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    Deanjames Member

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    [Feb 6, 2013]
    Hi this is my first post just wondering if someone can help me.

    I got a 02 plate A4 1.9 tdi the Temperature gauge in the car don't move just sits at 50.

    Today I have replaced the Coolant Temp Sensor with a genuine part, I was hoping this would resolve the issue- NOPE

    I have VAG COMMED the car and i get

    17664/P1256 - Engine Coolant Temperature Circuit (G62): Open / Short

    And advise is appreciated

    Dean :)
    #1
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  3. stu_m
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    stu_m Well-Known Member VCDS Map User

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    [Feb 6, 2013]
    did you replace it with a genuine Audi part? or an ebay special ?

    if a genuine part I would start by checking the wiring

    have you also cleared the code and did it come straight back?
    #2
  4. Deanjames
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    Deanjames Member

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    [Feb 6, 2013]
    Yup a genuine part as posted.

    Any idea what wiring to check? Im handy with my corrado vr6 the audi is all new to me.

    Could it possibly be the thermostat ? But then saying that i would expect it to at least see a temp.
    #3
  5. stu_m
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    stu_m Well-Known Member VCDS Map User

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    [Feb 6, 2013]
    ooops didnt notice the genuine part bit

    the stat wont cause the error code you have unless the error was there from the old sensor and just not cleared did you clear the code and it came straight back on if so you have a wiring problem which I would check the wiring that goes to the plug one of the pins could be off or a break somewhere

    If the code was not cleared then cleared it first if it stays off then change your stat

    Do you get heating and is it good? if you get plenty of heat then I dont think it will be the stat
    #4
  6. Audi Doodah
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    Audi Doodah Active Member

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    [Feb 6, 2013]
    Is your replacement stat green in colour? The green ones have two sensors in them, one for the ecu and one for the gauge. There are similar looking black ones available which only have one sensor. The green one is the one I replaced on my 1.9 TDi.

    If you have got the correct sensor then the first thing I would check is the stat connector. When replacing mine, one of the pins pushed back and gave me the same fault as you. A bit of fiddling with a small screwdriver got it locked back in place.

    Hope this helps!
    #5
  7. StuG808
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    StuG808 1.9tdi130 Avant FailWheelDrive

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    [Feb 6, 2013]
    My heating worked fine and I had a faulty stat. Based on experiences that others have had on here, I would change the stat in the first instance before the sensor as its easier, cheap, and more likely to be the culprit.
    #6
  8. stu_m
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    stu_m Well-Known Member VCDS Map User

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    [Feb 6, 2013]
    So you think the error code is nothing to do with the sensor but the stat?

    If the gauge isn't working and you have an error code pointing to the sensor then there is a problem with the sensor!

    If it was just the stat then the needle would move a little as they always do when the stat goes it just doesn't get to temp
    #7
  9. B5NUT
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    B5NUT Well-Known Member VCDS Map User

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    [Feb 6, 2013]
    If you get an error code which states open/short and you cannot clear the code then there is your fault, it has nothing to do with the thermostat, anyway it's easy to check the stat, just make sure both top and bottom hoses going to the rad are hot. My guess is you either have the wrong temp sensor, the new sensor is faulty (very unlikely), the pins on the plug are corroded and need cleaning, or a broken wire which is most likely, try and strip some the cable back to see if the break is near the plug.
    #8
  10. gavsman
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    gavsman Member

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    [Feb 7, 2013]
    I changed my CTS last year & that sorted out the erratic up & down of the needle on the gauge, but it would still never get over 70 Degrees, so I changed my thermostat & topped up with about 2 litre's of Coolant & water last weekend & after about 8 minutes on a run it went straight to 90 Degrees & stayed there.

    Thermostat part: 044121113 ( £21.77 inc VAT)
    o'ring: 038121119B (£ 2.90 Inc VAT)

    G13 Coolant - This has replaced G12 & G12+ ( £10.46 for a 1.5 ltr bottle)


    These are the part numbers quoted to me from Audi Dealer for my PD130 AWX engine.

    As STuG808 & others have said this is very easy to do - as long as you have a ratchet set with extension bar, takes about 30 mins max ( which includes topping up the coolant)
    Take engine cover off, right hand side as you look in engine behind the alternator, 2 10mm bolts to undo the housing, wiggle the housing off ( coolant comes out, pull out old thermostat ( more coolant comes out), put new one in the same way the old one came out, place o'ring over the thermostat, put housing back on & do up the 10mm bolts, then top up your coolant.
    I think STuG808 & Quattrojames put an "exploded" diagram from Elswin on one of there posts that shows you exactly how it all goes together.

    For peace of mind I would change both.
    The CTS is a little fiddly to do but not hard & you will loose coolant, so better to do both jobs at once.

    Coolant Temp Sensor : 059919501A

    O'Ring: 90316802N

    CTS Clip: 032121142


    Not sure on prices for the CTS for Audi as I purchased mine from Eurocarparts ( about £10)
    Last edited: Feb 7, 2013
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  11. StuG808
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    StuG808 1.9tdi130 Avant FailWheelDrive

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    [Feb 7, 2013]

    Ah just checked and 50 is effectively 'zero'! So probably not the stat!

    Carry on..
    #10
  12. pauldazzle
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    pauldazzle Active Member

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    [Feb 7, 2013]
    If the code was cleared, & it's come back again either the sensor is goosed or the wiring/connector.
    #11
  13. Deanjames
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    Deanjames Member

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    [Feb 14, 2013]
    ***UPDATE***

    I have replaced the CTS with a gen one and cleared the code - Code has not reappeared.

    I have replaced the thermostat.

    Still have no temperature guage in the car and sits at 50.

    I noticed that the two hoses that connect to the radiator only the top one gets hot, the bottom hose that leads from the thermostat to the bottom of the radiator is freezing cold, so that hose is getting no coolant to it.


    The car had a new gen cambelt and water pump 4k ago.

    Also the radiator only gets hot at the top and not the bottom.

    I am now thinking blocked radiator or waterway ?
    #12
  14. stu_m
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    stu_m Well-Known Member VCDS Map User

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    [Feb 14, 2013]
    Theres nothing wrong with the bottom hose been cold it is your cold inlet back to the engine

    The rad will cool it enough to make it feel cold it sounds normal to me

    It could be a duff gauge
    #13
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  15. Deanjames
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    Deanjames Member

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    [Feb 14, 2013]

    Ok so the bottom hose is suppose to be cold? Now I am really confused.

    If the hose connecting the thermostat to the fan is cold and the coolant cold the thermostat is never going to open.
    #14
  16. pauldazzle
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    pauldazzle Active Member

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    [Feb 14, 2013]
    Stat should open at approx 88 degrees & then the bottom hose should get hot. If it doesn't you have any of the following. Faulty stat, air lock, failed water pump or a blockage.
    #15
  17. Deanjames
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    Deanjames Member

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    [Feb 14, 2013]
    Thanks Pauldazzle Stat is new and gen so doubt it is that, waterpump is gen and has 4k on it and can see it working. Must have a blockage somewhere.

    Could the radiator be at fault
    #16
  18. stu_m
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    stu_m Well-Known Member VCDS Map User

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    [Feb 14, 2013]
    A picture says a thousand words!
    [​IMG]

    If you let cold water in the top it would have to go all the way round the engine before it reaches the stat which then the stat would close and all the water in the engine would be stone cold
    #17
  19. pauldazzle
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    pauldazzle Active Member

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    [Feb 14, 2013]
    To flush the rad out remove top & bottom hoses & flush out both ways.
    #18
  20. pauldazzle
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    pauldazzle Active Member

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    [Feb 14, 2013]
    Getting the air out of the cooloing system can be a pita.
    Turn the heater to full hot.
    Fill the system with correct mixture of G12.
    Leave the header tank cap off, start the engine & hold rpms to 3000 until it gets up to normal operating temp & the heater is blowing nice & hot. Check coolant level periodically, & hold the rpms up for another 5 mins or so. It's worth giving the top & bottom hoses a squeeze once the bottom hose has got warm too. Top up if neccessary & leave the engine to cool down. Check coolant level & replace the header tank cap. Go for a run & check levels again.
    #19
  21. stu_m
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    stu_m Well-Known Member VCDS Map User

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    [Feb 14, 2013]
    I don't think there is a blockage as if there was your car would get red hot not stay cold!

    You have verified that water is going through the rad because half of it is getting warm which is normal

    To see if your gauge is actually working look at it before you turn your ignition on it should be dead bottom as in below the 50 mark very slightly when you put your ignition on it should rise very slightly to 50 it will only move about 2mm if it doesn't move at all I would start looking there

    If you have access to vcds you can check the temp with that to verify that the sensor is working and to check that the stat is keeping the coolant at around 90
    #20
  22. Deanjames
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    Deanjames Member

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    [Feb 17, 2013]

    thanks stu_m it's a strange one, I don't have a full version of VAG com to check the temperature of the sensor.

    i am now getting no fault codes on vag com and with the diag reader I have.

    when I start the car the guage does not move at all.


    I now starting to think it an electric fault
    #21
  23. stu_m
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    stu_m Well-Known Member VCDS Map User

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    [Feb 17, 2013]
    If the gauge doesnt move at all then there is something wrong with it

    could be anything from a broken wire to bad connection in the clocks
    #22
  24. gavsman
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    gavsman Member

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    [Feb 17, 2013]
    Haven't tried myself with VCDS lite, but can you do this test on it:

    1. go into the Instrument Cluster control module (-17-) and select OUTPUT TESTS (-03-).

    2. Click on the START/NEXT button to initiate a sequence of tests. The first of these tests the sweep and calibration of the analog gauges. The needles for all four gauges (tach, speedo, coolant temp, fuel level) will drop to 0, sweep slowly all the way to their maximum, and then drop down to a calibration position. These positions are:

    Tach - 3000 RPMs
    Speedo - 62 MPH (100 KPH)
    Coolant Temp - 190°F (90°C)
    Fuel Level - 1/2 tank

    I would guess if the temp gauge doesn't move at all on this test then then must be either an electrical prob or the dial is duff.
    #23

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