mine was going the other way, up past 90 onwards to 100.

Had the dash pod changed and all was ok, maybe could be the sender unit ?, or even worse the dash pod again :?

 

I thought 51 on the CC panel was oil temp (takes longer to hit 90 than the coolant guage on the dash). 49 is the coolant temp I think and that should read exactly the same as the dial on the dash.

(wrong again: http://www.********.co.uk/ttforumbbs/vi ... t=oil+temp)

 

I didnt think any CC settings were oil temp!

Its possible if you are still running an original temp sensor (black) that maybe its output has failed!
http://www.wak-tt.com/tempsensor/tempsensor.htm

It has a number of pins and the dash will feed of one, the ecu /cc of the others.

If your lucky its only this. :?

 

Any chance that a 5 mile journey on a cold day meant they got different temp readings (or do they both use the same sensor?)

Maybe try a longer test?

 

unlikely, the two sensors physically sit in the same housing, but usually one 'half' fails rather than both at the same time... the older black ones, as Wak says, are more prone to fail

 

..

 

Not entirely sure about my information there Wak. Just it seems 51 gets to 90* that bit slower than 49. Both hit 90degrees and sit there from what I can tell.

What else could they be measuring? (one's coolant for sure right but that seems to be 49 - unlike the A4 code (from AudiWorld) where it's 51 - none of the other codes from the A4 would get to that temperature as far as I can see so I couldn't think what else it is). This morning (it was about 4deg outside - car was in garage) - Started the car - both 49 and 51 read ~15* - Drove for 5min and 49hit 90* just as the dash display did - another 5min later 51 hit 90*.

Could there be multiple sensors for coolant? Does anything else run at about 90*? (I'm presuming it's not EGT as you've had a sensor fitted for that)

I thought you intelligent bods discussed this a few weeks back. maybe I missed something.

EDIT: THEY DID AND I MISSED THE BOAT - SEE HERE: http://www.********.co.uk/ttforumbbs/vi ... t=oil+temp

Rhod

 

I think the concensus was that 49 varies and is perhaps temp on one side of the thermostat and hence why it changes, perhaps from the radiator.

51 is coolent temp on the engine block side as its more consistent.

49 can take a while to rise and seems to be in line with the radiator getting airflow or not if in traffic.

:?

 

Trouble is Wak I don't see how it can measure two separate temps, there is only one temp sensor and that is G2 which is on the radiator side of the thermostat. The only other possible sensor is the combined oil level/temp sensor G266 in the sump

 

Trouble is Wak I don't see how it can measure two separate temps, there is only one temp sensor and that is G2 which is on the radiator side of the thermostat. The only other possible sensor is the combined oil level/temp sensor G266 in the sump

isnt there a sensor on the radiator itself that contols the fans? could it be that?

Next time your out for a run chip, try 51 its behind the dash but stays at 90ish when its caught up.

then try 49, it varies and increases in traffic. :?

 

I like the idea that 51 show the oil temp from G266. Someone prove it please ;-)

Clive

 

I too have had problems with my dash temp guage this week. Since I bought the car in June, the temp has sat at 90.

But this week its gone up to 100 and even above yesterday! I've got plenty of coolent and oil in the car, and it was serviced my Audi about 4 months ago.

I'm hoping the engine is actually fine, and its a faulty guage/sender/pod (its booked in with Audi on the 16th to be looked at). However I'm goona look at the aircon code to make sure I'm not 'really' overheating.

However, I have a few questions. What is the temp sensor on the dash measuring? Oil, coolent or just the engine temp?

Also, which code do I use to replicate the the dash sonsor on the air con unit? I want to try to prove that its the dash sensor that is faulty.

Thanks in advance guys.

Dave.

 

I like the idea that 51 show the oil temp from G266. Someone prove it please ;-)

Clive

that would be nice

I have found some info on a measuring block that may be oil temp

I'll have a look later in vagcom and see if I can get the CC to match.
:?

 

Just been out for a run to play with the cc codes.

As Wak says, 51 is behind the dash reader, but gets to 90c eventually and stays there.

49 gets to aroung 90, but goes above when in traffic.

But as I've said, the dash reader goes up over 100c. Can I assume that the dash reader is faulty if cc code 51 is telling me 90c ??

Cheers all,

Dave.

 

Trouble is Wak I don't see how it can measure two separate temps, there is only one temp sensor and that is G2 which is on the radiator side of the thermostat. The only other possible sensor is the combined oil level/temp sensor G266 in the sump

isnt there a sensor on the radiator itself that contols the fans? could it be that?

Next time your out for a run chip, try 51 its behind the dash but stays at 90ish when its caught up.

then try 49, it varies and increases in traffic. :?

There are two radiator fan switches, but they are just that - switches not sensors - and they connect to the fan control unit J293, but AFAICS there is no information back to the AirCon from there. The oil level/temp sensor (dashpod green connect pin 15, labelled oil level/oil temp) is the most likely source of the second reading, fed onward to the AirCon via CANBus data as is coolant temp.

I would surmise that coolant temp in feed to radiator lags oil temp as coolant in rad not heated until thermostat opens. Oil is cooled by water jacketed oil cooler (between filter and block)

gut feel - 49 is real water temp, 51 is oil temp which i would expect to be more static

 

Going a bit off topic now... but Wak don't you have an oil temp guage in your guage pack. Surely the reading from that will give a good indication as to whether the 90* reading from 51 is of the right order or not?

 

Irving, I have had situations where the "oil" reading actually is ahead of the coolant temp - just last week in fact - v. cold morning, stuck in stop start traffic - "oil" reached 90 long before coolant did - but then my coolant number often sits between 84 and 90.... and then will obviously go higher when pushing on.

I do have an additional oil cooler too, but that thermostically controlled I believe, so shouldn't make any difference to how long it takes for the oil to reach op. temp.

Clive

 

Going a bit off topic now... but Wak don't you have an oil temp guage in your guage pack. Surely the reading from that will give a good indication as to whether the 90* reading from 51 is of the right order or not?

Its A/F Ratio, Volt meter and Exhaust Gas Temp on the guage pack. :?

I've finished playing now... and I'm fairly certain none of the CC display options are oil temp and none are even close enough to use as an oil temp indicator :? Oil temps rise a lot slower than the coolant temps

(bare in mind I only looked at this at idle in the front drive from a cold engine start and I do have an oil cooler and its possible that the oil and coolant temps are 5-10 degrees different because of the additional radiator, when the coolent indicators were at 90, my oil temps were at 80)

On the CC the A4 settings mostly match, not all but in general you can check out the CC inputs from this page.
http://www.wak-tt.com/tt/climatecontcodes.htm

The most useful CC settings are:-
20C volts (measured at the CC compressor clutch)
49C = Coolant temp - accurate
plus
48C display test (lights all the pixels on the CC)
51C = Coolant temp (smoothed or filtered)

49C is the one to use for temps, it doesnt follow the dash but then niether does 51 but 51 is closer to the dash readings.

49C is real temp IMO, it rises over 90 and you can switch off econ kicking in the A/C fans and see it drop, it changes more realistically.

I have used 49 in traffic on cold days and switched to auto if it rises over 90.

I have some pics and update to my vagcom pages which I'll try to do later.

On VAGCOM if you select instruments 17 you can look at block 050 and you will get the real oil temp reading.

There is also an Oil Pressure block but it seems to be a 1.2bar min pressure indicator switch, only shows OK if everything is running above that pressure.

 

Wak, I think 51 does "follow the dash" - so long as you remember that the dash is centre weighted - so when it reaches 80-something it goes to the middle and doesn't move till it's over at least 95 - which as we know is done purely so that customers don't worry about minor variations all the time when the car is within the normally operating range. Outside of this weighted area, it tracks 100%.

Clive

 

Wak, I think 51 does "follow the dash" - so long as you remember that the dash is centre weighted - so when it reaches 80-something it goes to the middle and doesn't move till it's over at least 95 - which as we know is done purely so that customers don't worry about minor variations all the time when the car is within the normally operating range. Outside of this weighted area, it tracks 100%.

Clive

ah, I didnt know that, learn something new every 5 minutes on this forum!

annoying that Oil temp is available but not one of the CC options I think sticking to 49 on the CC is the best option for anyone wanting a litle bit of additional info.

I'm hoping AmD's new box will be able to tap into more of sensor inputs for display so maybe Oil Temp will be an option. :?

 

Some new info for vagcom owners:-
http://www.wak-tt.com/vagcom/vagcomlive2.htm

Oil Temp reading
Brake/Clutch/Cruise Switch checking
Fuel sender reading

 

Sorry Wak, oil temp did you say?

Seriously Wak, good discovery. This should enable us to work out 49 and 51 at last. Just wish I had a TT sat in the garage I could go try it on.... :roll:

 

Sorry Wak, oil temp did you say?

Seriously Wak, good discovery. This should enable us to work out 49 and 51 at last. Just wish I had a TT sat in the garage I could go try it on.... :roll:

yup but in the instrument diags through vagcom and not an option on the CC display!
:?

 

Current Dashpod has been in about 14 months. The temp guage sat on the 90c mark beautifully until yesterday.

Due to a business trip the car had sat outside the house since Friday, and yesterday I go in a drove my usual 5 mile trip to work. The guage bearly made it to the first graduation!

So using the CC Controls I set up no 51 to watch the temperature going home and watched the temp rise to exactly 90c, but the guage still says about 45c

Is there anything I can do to recallibrate the guage or does it look like a visit to the freindly dealer?

In response to Richards original question, if you log block 50 on the instrument cluster through vagcom.

It should tell you if its actually recieving 90 degrees and the motor is not working or tell you its recieving a value equal to the displayed value implying a sensor problem.

I think the 51 on the CC is going to be accurate to the cluster but maybe worth this check to confirm. :?

 

Sorry Wak, oil temp did you say?

Seriously Wak, good discovery. This should enable us to work out 49 and 51 at last. Just wish I had a TT sat in the garage I could go try it on.... :roll:

yup but in the instrument diags through vagcom and not an option on the CC display!
:?

But then we can see if the two (vagcom and cc) match...