Changing The Temperature Sensor Of MKIV VW/Audi, Jetta, Golf, 1.8T DIY

Fix Temp Sensor DIY


Recently my temperature sensor had gone out on me again, and so i figure now around I’ll take some pictures and save everyone a couple of hundred dollars from the dealership. Most of the original sensors positioned in the MKIV cars were faulty and instead of a recall VW/Audi was nice enough to developed a new revised part and let us pay it off. The revised part number is 059-919-501A and will possess a green top as opposed to the original black or blue top that was in your car. No matter if you drive the Jetta, A4 and Passat Beetle or GTI this should be the right replacement part, but make sure with your local V-dub dealership. For some reason all the dealerships are charging a different amount for this part so anticipate paying anywhere from $25-$40 for this fix. The part can also be bought at Autozone for $8.99 (part # SU5404), I have heard mixed results with using the autozone part but it does come with a two year warranty. An alternative is to buy online to save some cash. I don’t trust most online stores but one good one for OEM parts is ECS Tuning. In addition to the sensor I might recommend getting a new O-clip and ring.

After the bad sensor is replaced you should see an increase in gas milage and it is also known to steady the idle along with making your in dash gauge work correctly again. So that as always lets give the stealership a call and see how much it will cost to do this 10 minute repair. The dealership quoted an amount of $161 tax for the repair, parts being about $38. So savings on this DIY is approximately $120.

Symptoms of a Faulty Sensor

Some cars will receive a check engine light when the sensor goes bad and some is not going to. If you have an error code go down to your local auto store and have them scan it for free. In case you are receiving these codes its likely your temp sensor.

Fault Codes:

17704 Error in mapped cooling system

01039 ECT Sensor

p1296 35-00



Quite often you will be able to tell that you have a negative sensor by the way your temperature gauge needle randomly floats around or stays at zero or even a fourth of the way up whenever your car is fully warmed up. When my sensor first went out the needle on the temperature gauge just stuck on zero. I took the sensor out gave it a good scrub and it lasted about another half per year (don’t be cheap as i am, just buy a new one), but both times I did not receive a check engine light so I’m guessing that’s just random.

If your temperature gauge is reading above 190 degrees more than likely it is not your temperature sensor yet your thermostat or even worse your water pump. Ouch! that’s gonna cost some money!

Tools & Part Numbers For the Job

This is a very simple fix only needing a flathead screwdriver and about 20 mins of time.

Sensor: 059-919-501-A or Autozone Part #SU5404

O-Ring: N90-316-802

Clip: 032-121-142

A few sizes of flat head screwdrivers


Coolant in your car after it has been running is extremely hot. So if you do not want to risk a 200 degree fahrenheit money shot right to your facial skin then will not attempt to change this sensor until your car or truck is completely cooled down.

I suggest the “”better safe than sorry”” method on this one and let your car cool down overnight, then do the repair every morning. Seeing the way the repair will simply take most people about 10 mins (thirty in the very longest) this could also be done before heading to work. An additional benefit of waiting till the car is bone cold could it be will leak very little coolant while swapping out the sensor. If you want to attempt this DIY while your vehicle is still hot use google to find instructions for that print and method yourself out the directions to your local burn victims unit in the event that.

The sensor is located in this general area

The sensor is located in this general area

Step 4

Step 4

Step 5

Step 5

Lets Get This Party Started!

Make sure your car is completely cooled off.

Loosen your coolant reservoir cap to release any developed pressure, then tighten the cap support. By doing this you create a vacuum seal then when you pull out the bad sensor very virtually no coolant will leak out while you are making the swap.

The temperature sensor is located directly off to the right of your valve cover as you can tell in the picture. If you have an Audi A4 or passat it is located between the firewall and valve cover while watching battery enclosure. If you’d like but you should have enough room with out removing it, you can opt to remove your engine cover. I can’t say beyond doubt because I have no idea what went down to my engine cover. To remove the cover push down on the twist and screws left (looking at it should be pretty self explanatory).

Once you locate the sensor wedge your flathead screwdriver between the clip and your sensor. If you didn’t want to go all out and buy the new 65 cent clip then be gentle therefore you don’t warp or break it. Now pull out the sensor though it may be still linked to the wire harness. If you are concerned you can place some paper towels under the hose before you remove the sensor, some coolant may leak out.

By using your fingers or possibly a small screwdriver, release the wire harness. I described these little clips before in one of my other DIY’s. Just use gentle pressure, no reason to show off for that ladies and get all he-man here. The clips can be fragile so the last thing for you to do is break it. Update: I just broke one off, Here is a diy on how to replace broken harness connectors when you accidently break yours.

Once your old sensor is released in the wire harness check to see when the o-ring is on it, In the event the o-ring is not on the sensor then dig it out of the hole with the little pinky finger. (Wow that brings back high school memories).

Prior to stick the brand new sensor in I like to lube up the new o-ring after some coolant to help you it all seal up properly.

Slide your clip in gently, plug the wire harness in and start up the car. Given that nothing is leaking out then you’re ready to go. If your coolant is low pour a bit distilled water in the reservoir to top it off (do NOT mix it with store bought coolant).

If you do have a check engine light on you have two options now. You can unplug the negative terminal on your car battery for a couple of seconds which can reset your fault codes or can can just ignore the light for about sixty miles and as long as which was the only problem the sunshine will shut off on its own.

comments and Questions: In case you have any please feel free to leave them below.

More Audi/VW DIY’s

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