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Temp Gauge not working

Discussion in 'Leon Mk1 (2000-2006)' started by Cupra TDI 150, Oct 5, 2012.

  1. Cupra TDI 150

    Cupra TDI 150 Active Member

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    Help !!!! My temp gauge isn't working on my 53 Cupra TDI, I used the search function and all I could find was about the thermostat.

    I'm not 100% it is the temostat, as on the right hand side of the engine is a wire going to what must be a sensor, its located under the air intake pipe from the air box. When I wiggle the wire and plu seems to work for a split second ie moves up to 90 degrees then back 0.

    Thanks

    Duncan
     
  2. Seatmann

    Seatmann Rough around the edges

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    Coolant temp sensor, 4 wires? It does the ecu and the gauge and if it goes the temp gauge doesn't work. Mine used to do the same, give it a wiggle and it went up so I thought it might be the wiring but no, a new sensor cured it.
     
  3. Cupra TDI 150

    Cupra TDI 150 Active Member

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    Yeah sounds right, it first started going up and down but now it just doesn't work unless you wiggle the plug. I've tried to take the plug off but i can't seem to gwt it free. How difficult is the sensor to change?
     
  4. Muttley

    Muttley Catch that diesel!

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    Not difficult, but you will lose some coolant. As far as the electrical connector is concerned:

    I have had some difficulty undoing other connectors under the bonnet, and found that there is a locking catch that must be disengaged by pulling the tab backwards, in the direction of pulling the connector apart.

    I've used the connector onto the brake fluid level sensor in the following photo's, because it's easy to get to.

    The plug looks like this, end-on, when it's apart.
    [​IMG]

    The socket is shown here, with the locking tab
    [​IMG]

    Here is a top view of the connector plug showing where the bit you pull on is located.
    [​IMG]

    This is how it comes apart.
    [​IMG]

    Hope this helps
     
  5. seatturbopower

    seatturbopower Active Member

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    new coolant temp sensor mate.change that for the green type one and a good priced one also.mine was 25 euro alot i know but a o.e one so all good.some have said that cheap ones are just as good but from i brought the car the guy said he changed it few weeks ago............i buy the car on the same day light comes on EML light.
     
  6. Cupra TDI 150

    Cupra TDI 150 Active Member

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    Any one got a part number for the temp sensor?
     
  7. randomage

    randomage Active Member

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    Just google them mate, they're that common to go that they're easy to find! I've had my 2nd go now, serves me right from buying a cheap one off ebay... Doesn't affect the car apart from the guage so far as I can tell, so I haven't bothered replacing it again. That and the fact it's held in with a makeshift clip, held on with about 4 plastic cable ties after the standard clip disappeared, allowing my engine to forcibly eject the sensor and most of my coolant - RAC men can be pretty imaginative!
     
  8. Muttley

    Muttley Catch that diesel!

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    randomage, the temperature sensor unit contains two separate sensors, one of which feeds the dash gauge and another which is connected to the ECU. If the dash gauge is inaccurate you need, at the very least, to have the fault codes scanned; but the trouble is if the sensor is merely reading wrong but not completely failed the ECU will call for the wrong fuel quantity from the injectors.
     
  9. randomage

    randomage Active Member

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    Huh, that would spell issues.. Well the gauge is completely non-functioning, which was solved last time by the new sensor, but I think it has just died completely, engine behaviour hasn't changed and I haven't seen any drop in power or MPG yet. I'll probably get round to replacing it next time I have a garage to play in, just annoying trying to do it outside in the cold, even warm coolant doesn't stop tender fingertips!
     
  10. Cupra TDI 150

    Cupra TDI 150 Active Member

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    All sorted now guys !!! Thank you all for your input. it was the coolant temp sensor. When changing the sensor be prepared to loose a fair bit of coolant so have plenty of rags about. I found removing the flexy pipe from the air box to gain better access

    Again thanks for all your help!!
     
  11. Seatmann

    Seatmann Rough around the edges

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    I leave the plug connected, swap the sensor over then the plug, it can make it a quicker job. Still an awkward sod on the tdi though lol
     
  12. greck999

    greck999 SLOW work in progress....

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    I changed my cts last night as my sensor was playing up and put my engine management light on. Temp always read ok on the dash.
    I changed it for a genuine vag part, a green sensor.
    Now the gauge hardly moves when I'm on the move. There is hot air from the vents and when I'm stationary the gauge will move to about a quarter.
    Would these probs occur if there was an air leak and the water wasnt able to touch the sensor as I lost a bit when the sensor went in. Not a great deal as the engine was cold.
    Hope somebody can help.
    It's an 04 LCR. Thanks.

    Neil.

    Sent from my HTC Desire S using Tapatalk 2
     
    #12 greck999, Oct 27, 2012
    Last edited: Oct 27, 2012
  13. greck999

    greck999 SLOW work in progress....

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    Help, please..

    Sent from my HTC Desire S using Tapatalk 2
     
  14. Cupra TDI 150

    Cupra TDI 150 Active Member

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    Have you checked the fault codes? Could possibly be thermostat.
     
  15. greck999

    greck999 SLOW work in progress....

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    I have scanned and there is nothing. I imagine it could be the thermostat but its strange how it has started to do this since I changed my temp sensor...
    :mad:

    Sent from my HTC Desire S using Tapatalk 2
     
  16. Cupra TDI 150

    Cupra TDI 150 Active Member

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    Oh dear, possibly faulty sensor? I only managed to work out what to try by searching the froum I wasn't really sure what if changing the sensor would work. I also lost a fair amount of coolant, well more than I imagined i would loose. It almost emptied the expansion tank. Sorry i can;t be more help.
     
  17. DrewCole

    DrewCole Spannering the Cupra

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    I did this very job last night, my gauge used to rise and fall, with the EML on.

    Since changing this my gauge doesn't move at all, I used the Green sensor too.

    I did loose some coolant so wonder if the level dropped too much and there is now air in the system, I'll try to bleed it and see what that does....

    Another job ticked off then added back to the list!
     
  18. dgjdrummer

    dgjdrummer Part-timer

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    The system is self bleeding, run it for about 10 mins with the coolant cap off and you can just give some of the larger pipes a squeeze if you're in doubt but they generally don't suffer from airlock or anything.

    Sent from potato.
     
  19. DrewCole

    DrewCole Spannering the Cupra

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    I played around with the plug on the sensor and the gauge on the dash started working when stationary, but dropped when driving.

    So think that would point to the thermostat needing to be replaced.


    Sent from my iPhone using Tapatalk
     

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