# Changed Temp sensor. still not reading correctly



## Nathapong (Jun 19, 2008)

just changed temp sensor in my 03 passat. still is problem. car warm needle gauge goes to middle 190 and then as i drive on the needle would go back to 0. and then it goes to half of the middle then back down to 0. what is the problem. do i need to get me Vag-com? some one pelase help 
Thank you sam


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## walkingfool (Mar 24, 2008)

*Re: Changed Temp sensor. still not reading correctly (Nathapong)*

Your description sounds more like a thermostat problem (or even a coolant level problem) than a temp sensor. Before I dove into the thermostat replacement (which means removing the timing belt) I would make sure that it wasn't an intermittent electrical problem, though. Check the temp sensor wiring for loose connections, fraying, cracks, etc- I'm sure you already did that when you replaced the sensor.


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## O_o (Nov 12, 2009)

*Re: Changed Temp sensor. still not reading correctly (walkingfool)*

Does it go up and down gradually or suddenly? If it's suddenly, then it sounds like one of:
1) baby needs a burp;
2) you have fubared wiring/harness;
3) it's not quite on properly (those clips are a bit of a pain), or;
4) you got a dud CTS (it happens).
If it's gradual, then it could be the thermostat, but I'd be surprised that it would go all the way to "0" after having warmed up, unless it were very cold out, and you were on a long highway drive.


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## Nathapong (Jun 19, 2008)

*Re: Changed Temp sensor. still not reading correctly ()*

it goes down suddenly. i just got my belt done at 70 k car have 83 k now. it might need a burp. i did also add a little more coolant to it. how can i burp this baby.?


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## afawal (Oct 18, 2005)

*Re: Changed Temp sensor. still not reading correctly (Nathapong)*


_Quote, originally posted by *Nathapong* »_it goes down suddenly. i just got my belt done at 70 k car have 83 k now. it might need a burp. i did also add a little more coolant to it. how can i burp this baby.?


Does it go down when you are driving and go back up when stopped or idling?
If so, then it's most likely your thermostat. If you had air in the system, you would have overheating issues.
Here's a test:
When you see the needle go down to 0, turn the heat on full blast and see if you're getting any hot air. If you are, then it's electrical, or maybe the temp sensor you put in is defective.
Good luck,
Keep us posted!


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## Nathapong (Jun 19, 2008)

*Re: Changed Temp sensor. still not reading correctly (afawal)*

yes there is still heat coming out of it.


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## dumped_gti (Dec 16, 2003)

*Re: Changed Temp sensor. still not reading correctly (Nathapong)*

You need to scan it with VCDS or better.


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