DIY: 3.0 G62 Green coolant temperature sensor replacement

B6 A4
#1

Made this a while ago for AZ…

This is a DIY to replace the coolant temperature sensor on a 3.0 engine. You will often get a check engine light when this part fails and you will get the code 16500: Engine Coolant Temperature Sensor (G62): Implausible Signal. Or you may get 16502: Engine Coolant Temperature Sensor (G62): Signal too high.

The part you need is the Green coolant temperature sensor. This is known as the G62 and they cost about $42 at the dealer where i got mine. JHM should be able to get all of these parts for you. I suggest not ordering from ECS dumbfuck crooks

http://img227.imageshack.us/img227/6127/tempcx3.jpg

You also may need the clip that holds the sensor in. its not necessary but i just replaced it. the parts guy at my Audi dealer said that sometimes they get brittle over time and it is best to just replace it. I paid $1.20 at my dealer but ECS has it for .56

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Tools you need:
3/8" Ratchet with a swivel head
5mm Allen head socket
10mm Socket
Philips screw driver
Pick to remove the old O-Ring
Clamp removal tool for clamps on intake hoses. (you can use vise-grips)

http://i183.photobucket.com/albums/x59/joec1992/DSCN0046.jpg

NOTE: You should do this on a cold engine to prevent being burnt from coolant when you remove the sensor. I suggest you loosen the coolant cap if the engine is even slightly warm.

First, unplug the MAF sensor that the red arrows are pointing to. Once you do that, you need to un-clip the MAF sensor from the air box. There is one clip that is circled, the other on is on the opposite side. Then remove the big clamp circled on the right and just slide it onto the accordion hose.

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Now pull the whole assembly off and set it somewhere where you wont step on it.

http://i183.photobucket.com/albums/x59/joec1992/DSCN0005.jpg

Now you need to tackle this mess.

http://i183.photobucket.com/albums/x59/joec1992/DSCN0037.jpg

First unplug this little guy. You should use a flathead and sort of work the hose off of its fitting. don’t try to pull it. doing that will only make the hose tighter and you might rip it or break the check valve.

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Then unplug this thing, whatever it is

http://i183.photobucket.com/albums/x59/joec1992/DSCN0036.jpg

Then remove the thing you just unplugged. it comes off the same way a buckle does.

http://i183.photobucket.com/albums/x59/joec1992/DSCN0035.jpg

Now remove the bolts holding on the plate. the allen by the fire wall is a 5mm, and the two bolts in front are 10mm sockets. Then you will be able to wiggle the plate out of there. I did it by sliding it to the passenger side.

http://i183.photobucket.com/albums/x59/joec1992/DSCN0007.jpg

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use a Philips and remove the clamp holding on the hose seen below

http://i183.photobucket.com/albums/x59/joec1992/DSCN0006.jpg

There is one bolt holding on the tube leading into the throttle body. Use a 5mm allen head socket and a ratchet with a swivel head. you may be able to do this with a standard ratchet, but the swivel head is pretty much necessary. Its a very long bolt!!!

http://i183.photobucket.com/albums/x59/joec1992/DSCN0028.jpg

this should give you a better idea of where the bolt is

http://i183.photobucket.com/albums/x59/joec1992/DSCN0026.jpg

Now you should be able to pull the intake tube towards the firewall, then it should come right out

http://i183.photobucket.com/albums/x59/joec1992/DSCN0021.jpg

the sensor is located on the passenger side, pretty much right by the passenger side head. You will see it. its green so it’s hard to miss

http://i183.photobucket.com/albums/x59/joec1992/DSCN0019.jpg

Unplug the harness on the sensor (i did not do this until later, bad idea) and then pull out the clip on the back side of it that holds it in. i wa sable to do it with my fingers.

http://i183.photobucket.com/albums/x59/joec1992/DSCN0015.jpg

now pull the sensor out. i forgot if you have to turn it or not. be prepared for about 2 quarts of coolant to spill out.
Use the pick tool to remove the old o-ring. chances are, it wont come off with the old sensor

http://i183.photobucket.com/albums/x59/joec1992/DSCN0018.jpg

http://i183.photobucket.com/albums/x59/joec1992/DSCN0017.jpg

now put the new sensor in, this picture sort of shows the orientation; the flat side is facing the fire wall

http://i183.photobucket.com/albums/x59/joec1992/DSCN0016.jpg

now slide the new clip in to hold it in place and put the harness on the new one. get your garden hose and give the area a good rinse to get rid of the spilled coolant

[B]Now go backwards int he DIY and install everything in reverse order.

Fill up the coolant resivour and leave the lid open!!
Start the car and set the climate control to HI. the blower does not need to be done. we are just doing this to get any air out of the heater core. hold the rpm’s at about 2500 for a few minutes and watch for any bubbles in the resivour. when you see bubbles, you are purging air out of the system. when the bubbles go away, let the car idle for a few minutes. then, just to be sure, rev the engine a few times to get rid of any air pockets. I let the car idle for 10 minutes with the cap open while i was cleaning up. then i took it on a short test drive.[/B]

http://i183.photobucket.com/albums/x59/joec1992/DSCN0051.jpg

#2

Joe that was incredibly usefull and can be used for more then just the coolant temperature removal. Well done.

#3

Joe I used this months ago replacing that damn thing. When he says spewing, he means it lol burnt my entire left hand with a glove on.

Great DIY and saved me tons of time compared to anything else I found.

#4

Nice details on that job man. You made me realize I forgot to let the air pockets out after I had that incident with the coolant stem.

What mileage do these sensors usually fail at?

#5

Mine went out in between 80-85k I do believe

#6

Nice write up … I especially like the response to the broken piece! :smiley:

My brother should probably replace his BEFORE the engine goes in the car!

#7

All this time I thought you were posting from two different accounts. There are two louts people, TWO LOUTS.

#8

My sensor failed at around 68k or so.

#9

On the shopping list…

Hahahaha I’m the one with the B6, my brother likes to help me mod it

#10

Is this the correct part # for the sensor?

#059919501A

I believe this may also cause hard starting w/ cold & radiator fans to kick on (throwing a P0117)
I will update if this solves my problem

thanks for the writeup!

#11

Just wanted to thank you for the writeup- made life easy

So I replaced the sensor and it cleared up my CEL and (hopefully) the rare hard start issue.

I was consistently getting a CEL every start (even though it started normally) with occaisional high radiator fan on cold starts (lasted about 30sec-min)

The o ring was toast and weeping so it was good to change anyway.
No CEL and it does idle perfectly smooth

*time to do this repair is about 30-40min.
skill level: easy

#12

I’m about to tackle this job myself. My sensor triggers the CEL each time it is about to rain. I think the barometric pressure change is just enough to make the sensor fail. After the rain is gone the CEL goes away. Strange.

#13

Just replaced the sensor and my CEL does not come on in the rain anymore. That sensor was a pain to get to. My intake had a lower hose that I could not get off so I could only move it out of the way. That mess of little hoses and wires had another hose coming up from the bottom to a T connection not shown in the pictures that was very difficult to pull apart and even worse to put back together. What are those little hoses connected to the blue inline filter thing? I just want to know how critical they in case I didn’t get the hose back on tight enough.

#14

it’s a vacuum hose of some sort. I would make sure it’s on there tight. A loose vacuum hose will only cause issues

That birds nest of wires and hoses is a pain in the ass. I couldn’t believe it when I saw it. I don’t get why they wanted everything to go to that plate

#15

I only disconnected the one hose to the check valve, then moved the whole thing over.
There was plenty of room and it only required loosening the bolts and that one hose.