Temperature gauge woes

spike said:
Hi Jon
Ref posts 9 & 10 of this thread, I'd say its an 80% chance the temp sender is on its way out

Cheers Spike
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Thanks Spike. I've bookmarked this thread so will keep an eye on it over the next few days...

bretti_kivi said:
depends. How warm outside?
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The gritters were out, but the outside temp was about 7, according to the dash. Felt colder than that, though... Tried revving the engine higher than I normally would before changing gears to see if it generated a bit of heat but the needle didn't seem to want to go back to 90!

Jon
 
My replacement sender is the 4-pin version. Any way of knowing if my 2003 TDi has the 4-pin version already before I remove it?
 
Just remove the connector Dan - if the latch is not easily accessible, you can rotate the entire sender, without removing it, so that you can open the latch and take the connector off.

Cheers,

Mike
 
Is the 2-pin sensor that is suitable for the 1.6 petrol BAD the same as the 2-pin one I've got in my TDi?
 
OK - I thought one of the roles of this sensor was to give the ECU the coolant temperature - if I've only got two wires coming out of it, and it's job is to send the temperature to the gauge, how is the ECU reading the coolant temperature on my car?
Is there another sensor somewhere? Is it actually built into the thermostat?
 
Dan, what are the wire colours you have? I've been looking at this in the manuals but no reference is given to a 2 wire system, even as far back as 2001.

The pinout of the 3 wire system is as follows:

1 - wire to dash panel
2 - Earth (G2)
3 - Earth (G62)
3 - wire from coolant temperature sender (?)

The flat end of the connector is pin 1, the rounded end pin4

I've put a ? in for pin 4 as it makes little sense, the way it's described in the manual.

Looking at the wiring diagram, pin 2 does indeed go to earth (brown/white), pin 1 goes to the dash (blue/brown) and pins 3 and 4 loop into and back from the ECU (brown/grey and grey/brown respectively).

Cheers,

Mike
 
Cheers - I'll have to check tomorrow as it's dark here now. Something doesn't seem right does it?
 
Dan, have you PM'd the Audi-heck....... from post 16 in this thread? It seems that he has overcome (partially) the same problem as you're encountering, so a few pointers from him would be the best way forward.

Cheers,

Mike
 
Ok so popped the old sender out today to have a closer look. Attached pictures - old one on left, new one on right.

The old (two-pin) one has this code on it 269514
The new (four-pin) one has this code on it 059919501A, and also an Audi logo.

Seems the black two-pin job isn't an OE Audi part.
So why I wonder does my car not have the correct sender, and why does it only have two pins/wires in the connector?

Is there an OE solution to replace this sender, or do I have to bodge the wiring to make the new sender fit the 2-pin plug as done by an earlier poster?
 
I made a mistake the 2pin sender I removed was the fuel temp sender. My coolant temp sender is indeed a 4pin one. Whoops :)
 
Hello people,

I am a new member here and new owner of 2002 A2 1,4 TDI. I must say that i love it, but after few days of driving it i noticed some problems. First is common problem of this thread. I hope you can help me..

First of all it is cold where i live, i mean -14 C:) so i wonder if the problem is because of cold or is it termostat or sensor failure.

The temperature gauge shows 0 for a long drive. Then it randomly starts to rise slowly, sometimes faster, sometimes slower and at the end reaches 90 when in movement. Then i stop but motor is still on for 10 minutes and temperature significantly drops, sometimes to 60, sometimes even to 0. And if i move again for longer drive it rises again to some level, or even 90.

So the question is: should i change sensor or thermostat? My car warms up and blows hot air after really short time, maybe 5 minutes, so if it would be termostat, shouldn't vents blow cold air?

Also, will this problem have effect on fuel consumption? Cause my fuel gauge drops kinda fast...

Thank you for your time

Regards, Darius
 
Hi Darius
First question. Does your car have the auxiliary Webasto coolant heater fitted ? Its like a mini central heating boiler which runs on diesel and it fires up automatically at temps below approx 6C. The unit continues its (noisy) wind-down cycle after the engine is switched off so its fairly obvious if the Webasto is fitted

Cheers Spike
 
Spike, i am not sure about this. I think there is no sound after the engine is off, maybe just the ventilator shutting down. But not longer then 5 seconds. Any ideas?

Thanks
 
This temp unit seems like a common problem.
Mine wanders all over the place too.
 
Apsaauga said:
Spike, i am not sure about this. I think there is no sound after the engine is off, maybe just the ventilator shutting down. But not longer then 5 seconds. Any ideas?

Thanks
Click to expand...

Audi stopped fitting the diesel powered heater sometime in 2002 so I think your car will have the auxiliary electric heater which only warms the cabin. That would explain why the heater warms up quickly even though the coolant temp is low. Your description of the temp gauge readings ties in with the car operating in very cold ambient temps, possibly with a thermostat which is not closing fully to keep the engine warm. Personally, I would try changing the thermostat as this is more likely to be the problem rather than the temp sender

Cheers Spike
 
This is interesting, something definitely needs to be changed.. Do you think this problem can cause bigger fuel consumption or some other problems to the engine?

Cheers
 
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