Why does my audi tt temp. gauge go hotter than engine temp. fans work changed thermosat , temp sensor ,and water is ok ?

SOURCE: 2002 audi tt overheating

It does sound like the dash pod is faulty. I have had dashes pass cycle tests but turn out to be faulty.
Check when the car is hot, that when you key off and then key just the ignition on that the gauges (fuel and temperature) move slowly and smoothly up to there correct position. If they move very quickly, almost instantly, to there position then this is a sign of a faulty dash.
Let me know the out come.

SOURCE: temp guage not working

It's most likely one of two things: 1) coolant temp sensor (meaning the gauge isn't working), or 2) stuck thermostat (meaning the gauge is working but the coolant isn't getting hot)

Start with the coolant temp sensor - it's on the back of the engine, somewhat near the top, toward the passenger side. On your car it's likely a blue sensor body (as is the CTS on my 99 A4 2.8). The easiest way to get to it is to remove the tube leading from the airbox to the throttle body. Take that off, and you can look down and see that there's a squarish plug with four wires plugged into the top of the coolant temp sensor (at the right angle you can see the color of the sensor - black, blue, or light green, but most likely blue on your car). There's a C-shaped retaining clip that holds the connector onto the sensor which must be pulled off (pull more or less straight back toward the firewall), and then the sensor can be unplugged. The sensor itself is just pressed into the opening in the block, not screwed in - you just have to pull upward to get it out (it can be tough - try opening the cap on the coolant tank to alleviate pressure in the system). The sensor is not expensive (around $25 from www.ecstuning.com - call them up with your VIN number to guarantee they send you the right sensor).

If you change that out, and it doesn't fix the problem, don't sweat it - it means your temp sensor was working, but replacing it was a good idea anyhow since they're prone to failure and can cause all kinds of wacky problems when they go. Next most likely problem is a thermostat stuck partially or fully open, and this is more invasive - it requires removing the front bumper, opening up the core support (with radiator and AC condensor), losing (and having to flush and refill) your coolant, and the removal of the serpentine belt and fans. It sounds horrifying but it's pretty easy actually.

I'd suggest starting with the CTS and see if it fixes the problem. If it does not, reply here and let me know and I can help you through the thermostat replacement if you're mechanically inclined and have the tools. If you're in the northeast, I can do either repair for you (I'm in the southern tier of NY) and save you a bundle over a dealership, and save you the aggravation of doing it yourself if you're not mechanical or don't have the tools or experience.

Colin Stickland

• 22516 Answers
• Posted on Aug 16, 2009

SOURCE: 2000 Audi A6 2.8l Coolant Temp. gauge not working.

changing the engine sensor is easy when engine is cold and make sure you refill with antifreeze ,Buy sensor first so you know what to look for its not expensive from a motor factor .i honestly cant remember ever changing one on this model but it must be around the head area somewhere

SOURCE: Code P0118 on Audi A4 - Related to Ignition Coil Problem?

Hi, the sensor on the engine (right at the rear end of the cylinder head) has two separate outputs. One drives the temperature gauge and the other provides data for the engine control unit. The output for the engine control unit is almost certainly faulty and the sensor will need to be replaced. It isn't an expensive item and's not time consuming to replace (1/2 hr) - so you could ask Audi to do it for you when they replace the ignition coils.
Hope that helps Matt..

SOURCE: where to find the coolant

The Engine Coolant Temperature (ECT) sensor on an Audi TT 1.8 Turbo: