# 18613 - Need advice on VAG-COM data



## What's a VR6 (Jul 24, 2007)

VAG-COM Release 409.1
Motronic ME 7.1.1G 0004
Software Coding : 00032
1 Fault found:
18613 - Performance malfunction in cooling system
P2181 - 35 - 00 - -
Keep in mind, I've read many other threads about this code.
My question is regarding the data that I've collected with the VAG-COM when on a 30-40 mins drive. From the measuring blocks, the coolant temperature in °C reached 97°C. This happened when I was pulling up to my place to park the car. I looked at this and looked at the temp gauge in the car and it showed a flat 90°C.

Now I've recently had 264/260 cams installed and a Neuspeed SRI. I also noticed on the invoice that the shop changed the green top sensor. Could they have installed a faulty one or should I be thinking about the thermostat? The car, jugging by the T° gauge seems to go up to the operating temp between 5-10 mins, which I think is normal.
Thanks for your input


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## staytuned (Mar 26, 2005)

*Re: 18613 - Need advice on VAG-COM data (What's a VR6)*

replace the thermostat - this fault is typical - the ecm has a set value when it should open and if not meet this is the byproduct - staytuned!


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## What's a VR6 (Jul 24, 2007)

Thanks
Not sure if I understand though. Why wouldn't the temp gauge go any higher than 90°C if the VAG-COM indicates over 90°C (97°C in this instance). Wouldn't this be a sensor that gives out a flawed reading (97°C) while the real temp is actually around 90°C ?



_Modified by What's a VR6 at 7:57 AM 5-15-2008_


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## Theresias (Feb 11, 2004)

*Re: (What's a VR6)*

The gauge in the cluster is "normalized", which means it will show always ~90 °C when the actual temperture is in the 80-110 °C range.


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## What's a VR6 (Jul 24, 2007)

*Re: (Theresias)*

I'll have a look at the thermostat then, since all signs seems to point to that. We'll see how it goes from there. What kind of price range am I looking at ?


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## staytuned (Mar 26, 2005)

*Re: (What's a VR6)*

here in the usa $20 or so dollars - easy to do - i keep stressing generating readiness codes - this often validates diag and repair - if you need procedures let me know


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## serge0101 (Jun 8, 2005)

*Re: (staytuned)*

Just a tip, not sure if you replaced the thermostat yet, but you might still consider your sensor.
I just had the same issue as you, my sensor went out last november, I bought the green top at the dealership and replaced it. About three weeks later the light came on again with code 
18613 - Performance Malfunction in cooling system.
I also searched and pple were saying it was the thermostat. When I called a local VW tech, he said that there have been quite a few cases where the new sensors were faulty and malfunctioned really quickly. My symptoms were similar to yours. I got the engine light and my temp gauge started to show lower and lower temperature (i.e. - at normal engine temp when the car i warmed up, the gauge would show my temp to be below normal/less than at center). It got to a point where my temp gauge would always show "COLD" (all the way to the left). I bought a new greentop temp sensor from http://www.germanautoparts.com (about $17 after shipping w/ the o-ring and clip), replaced it in about 10mins, and the light was gone and the gauge was functioning back to normal. My MPG also went back to normal.
So just a tip, you might want to try that first before you replace your thermostat and realize you still have the same problem. I'm glad I did.
For more on the story, see thread here: http://forums.vwvortex.com/zerothread?id=3622775


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## mechsoldier (Aug 14, 2004)

*Re: (serge0101)*

Usually when the temp sensor is bad when viewing the coolant temperature it will jump around wildly. The way to check your thermostat since they normally fail in such a manner as to stay open rather than stick closed is to find a large hill if possible and coast down it, if you see the coolant temp drop below 86 c then you know it's the thermostat. Green temp sensors normally don't fail, I've replaced 2 or 3 ever, the black ones fail all the time. Also check for corrosion or coolant in the actual connector as that will do it as well. 
As far as readiness goes, I pretty much never set it, it doesn't have anything to do with the cooling system anyways. It really only monitors
O2 sensors, Secondary air, Catalytic converter function, Evap function, Purge valve function, and some other random stuff that most people will never need to do anyways. Normally I just run the basic setting or adaptation of the particular system I've serviced.


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## gehr (Jan 28, 2004)

*Re: (mechsoldier)*

Would temp. sensor failure cause the car to not start when hot and run rich, so much so it smells like a gallon of gas on the ground??!!


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## mechsoldier (Aug 14, 2004)

*Re: (gehr)*

It can, I had it happen to me on a Passat once while it was in the shop. I test drove it, repaired the car, went to start it up and drive it out and it wouldn't start and there wasn't even any faults in memory. CTS was bad, causing the car to think it was much colder than it really was. Try holding your foot to the floor and cranking it to get it started.


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## What's a VR6 (Jul 24, 2007)

I changed the green top sensor maybe a week and a half or two ago, deleted the code and the MIL didn't come back. Knock on wood. 
Had a look at this page (http://wiki.ross-tech.com/index.php/18613/P2181/008577), did all the tests they proposed and everything pointed to the sensor. Plus it's a cheap fix and a good first place to start http://****************.com/smile/emthup.gif 


_Modified by What's a VR6 at 5:31 AM 6-12-2008_


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## serge0101 (Jun 8, 2005)

*Re: (What's a VR6)*

Thanks for letting us know the result. Seems like you had the same issue I had. I'm just glad that I did not change my thermostat first as some people suggested, but tried to replace the sensor first. Although I'm sure that in most cases, the thermostat may be the issue . . .


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