So, Guys well im stumped here, lets start off from the beginning, I have a 96 a4 2.8L about a month ago my check engine came on, so what did I do? pulled out the old vag hooked the sucker up, got me a code P0118 my temp sensor bad, so I was like great now try to find this thing. finally found it and man it is not easy to get to I will tell you that, went to my local dealer purchased a sensor around 40$ yeah I know so the guy was like audi has replaced your temp sensor no more black squared one, here is this green one should fit. so I get down to the sensor, replace it reset my check engine light, drive for about a day noticing now. that I could have sworn my temp gauge would sit at 12 o clock, well with the new sensor in it doesn't sit there it will sometimes get up to there but when it does after driving for a while it keeps fluctuating from very cold to 12 o clock, No matter how long I drive with this new sensor in.

So I cant remember if it did this before, well besides it doing this it is still throwing error codes and check engine, So I talk to a local repair shop he says oh you got the wrong sensor, so he orders me some replacement black one, well put this one in and it does the same thing, if anything it throws my engine light on quicker, so Im like damn, I can't remember if my original one did this or just threw my check engine light? well so I decide I am already about 80$ into this plus time, keep in mind I got two sensors now that don't work. both making my temp gauge bounce between middle and cold.

so what the heck for ***** im going to throw in the sensor that initially threw the code. put it in, same thing? so im back to my orig faulty sensor and still problem with my temp gauge and my check engine light? I would also like to add during the initial change of the first sensor I had flushed my engine coolant and hydrolic fluid? dont think this has anything to do with it but? incase? im desperate here? also you know the area under the plastic casing for the hydro fluid with the wire connectors? is one of these my temp sensor connector? see photo below?


ORIG BLACK ONE Part #058 919 501A
GREEN SENSOR Part #059 919 501
SUPOSADLY NEW BLACK SENSOR Part #058 919 501A
*doenst have audi vw logos like orig and green one?

[IMG]local://upfiles/13253/625876A7A9C64F62B7B2B1250FEB23D1.jpg[/IMG]

[IMG]local://upfiles/13253/E7E6B46AFC0E49E29CDC9D702092FFE6.jpg[/IMG]

 

Make sure the connections are clean. You may want to use some stabilant on them too. Also check the wiring for any shorts. Sounds like you have more of a wiring-connection issue more than a sensor issue.

 

Thanks where is the location where the other side connects to? where would it be in the engine compartment? how would you reccomend testing for short? I could wip out the old voltometer? thanks very much, also is it possible to test the sensors manually with a voltemeter? it would vary in ohms? from hot to cold? thanks

 

usually if the car throws code for temp sensor the thermostat is bad and needs replacing, just remember that codes only tell you what sensor is sensing a problem but not what the actual problem is, if you got coolant tempature sensor code the sensor probably saw a problem with the tempature of the coolant, common issue is thermostat being stuck open for this code.

 

Shouldn't be the themostat, his engine is warmed up and he gets false cold indication.

 

it could be the thermostat and also an air lock that's why the gauge jumps, book says thermostat/sensor/air in system

 

he said that when he drives it, it cools down, sounds like thermostat to me, and ive seen coolant temp sensor throw more times than i count for a stuck open thermostat.

 

thanks also I ran the diag on the climate control for 51 which is coolant temp? which when the car is cold. it shows 0.0 but works its way up to 9.0? and stays there this is my reading I get on my climate control? got this from the secret audi codes haahha



Your Audi Climate Control Console has a diagnostic code that can enable you to access your digitally displayed speed, in kmph by pressing certain buttons in a certain manner.

51 Engine Coolant Temperature (ECT) in deg C

 

I also have this same problem. I've got an '01 A4TQ, and I've got the same error code. My temp. guage usually runs just a little bit cold (11:00) except it stays perfectly in the middle when I drive uphill. As soon as I start going on a decline or down a hill, the temp. guage will get cold.

Now I live in Colorado, and when I say decline I'm referring to a mountain pass, going from about 10,600' to around 7,500' in elevation in a matter of about ten minutes. During this time, my temp. guage will go ALL the way cold, until I return to a flat surface. Does this sound like it has to do with the thermostat?

I used to have a '95 BMW 325i and as I recall the thermostat was replaced probably like three times in only about four years....and there were different symptoms that came up each time it went bad. None of the problems in this BMW were the same as what I'm dealing with now...any ideas???

Thanks.
LampyB.

 

I would like to post a update. I recently had my 60,000 service done, and well you know whats included in that timing belt waterpump, thermostat etc. and well that seemed to fix my coolant temp issue? just thought I would post a update! thanks!