MK7 "Random / "Stupid" Questions Thread"

[Treadup]

Can you delete threads? I should have made a “part out thread”. I wasn’t expecting to get most stuff off the car in a few days.

 

[Salami]

Can you delete threads? I should have made a “part out thread”. I wasn’t expecting to get most stuff off the car in a few days.

Threads no. Posts yes.

 

[kyLman]

Anyone want to play a game of parts cannon with me? My guesses and symptoms are below:

A) Waterpump / Thermostat (did I get 2 bad water pump assemblies, stuck open therm?)
B) N82 Shutoff Valve (stuck open?)
C) Aux water pump (doesn't this usually throw a code?)
D) Heat Core (plugged up?)

Symptoms:
Under 40degF, car takes a long time to get to temp but will eventually.
Over 40degF, car has no issues creating and holding temp.
Once the car eventually does get to temp, the heat works fine (although should be a bit warmer, it used to sweat me out.) However, once I start idling in the driveway/red light, the cars temperature starts to plummet again.
Running OBD11, I see the coolant shutoff valve is always "open." I would imagine this is supposed to stay shut until a certain temperature parameter is met?


I had already replaced the waterpump assembly last year around this time, using a euro indy shop. The first waterpump assembly had a failed thermostat out of the box (car never got close to operating temp.) The shop changed the pump again under warranty, however it was spring time... so I never saw any days below 40deg again. Alas, it's finally cold again.

I've got a temp gun, if there's a way to diagnose, please I am all ears. I have a date in a couple of weeks with the euro shop again, but you know how it goes...

 

[Subliminal]

Anyone want to play a game of parts cannon with me? My guesses and symptoms are below:

A) Waterpump / Thermostat (did I get 2 bad water pump assemblies, stuck open therm?)
B) N82 Shutoff Valve (stuck open?)
C) Aux water pump (doesn't this usually throw a code?)
D) Heat Core (plugged up?)

Symptoms:
Under 40degF, car takes a long time to get to temp but will eventually.
Over 40degF, car has no issues creating and holding temp.
Once the car eventually does get to temp, the heat works fine (although should be a bit warmer, it used to sweat me out.) However, once I start idling in the driveway/red light, the cars temperature starts to plummet again.
Running OBD11, I see the coolant shutoff valve is always "open." I would imagine this is supposed to stay shut until a certain temperature parameter is met?


I had already replaced the waterpump assembly last year around this time, using a euro indy shop. The first waterpump assembly had a failed thermostat out of the box (car never got close to operating temp.) The shop changed the pump again under warranty, however it was spring time... so I never saw any days below 40deg again. Alas, it's finally cold again.

I've got a temp gun, if there's a way to diagnose, please I am all ears. I have a date in a couple of weeks with the euro shop again, but you know how it goes...

Oil maybe too thick?

 

[EpicTech]

I think you have a restricted coolant line somewhere, clogged up or something. Just a guess.

 

[DIB's]

thermostat question from total ignorance, haven't (yet) had to pay any attention to mine... ((knocks wood))

Are the thermos electronically controlled or old school spring/wax or whatever?

 

[Pineapple]

Pinging the wiring wizards @ZERO815 @DV52 @StorableComa with an easy one:

My base model (no LP) '17 GTI was factory equipped with a headlight switch with no auto position. If I complete the mk7 euro taillight retrofit with the necessary wires and harnesses and coding to enable the rear fog lights, but install a euro headlight switch with an auto position, will I get an error every time I pass auto on the selector?

 

[DV52]

thermostat question from total ignorance, haven't (yet) had to pay any attention to mine... ((knocks wood))

Are the thermos electronically controlled or old school spring/wax or whatever?

@DIB's : hmm.......... no - the thermostat(s) on MQB platform cars use electronic devices because they are peripherals (meaning inputs) to the electronic control units(s). This means that the Engine Control Module (ECU) in this case needs to read the "value" of the thermostat and make a determination about what's happening to the coolant temperature.

In the wiring diagram, the thermostat ( called "N82") looks like this:

Notice that N82 is a simple 2 x pin device shown as a rectangle with an arrow. In wiring diagram speak this means a variable resistor.

The thermostat is a transducer whose resistance varies with temperature - so not surprisingly, it's called a "Thermistor". I'm not sure with absolute certainty - but my hunch is that these are "Negative Temperature Coefficient" (NTC) Thermistors - meaning that as temperature increases - resistance decreases. There are Positive Temperature Coefficent Thermistors - but NTC type are the more common.

Don

 

[DV52]

Pinging the wiring wizards @ZERO815 @DV52 @StorableComa with an easy one:

My base model (no LP) '17 GTI was factory equipped with a headlight switch with no auto position. If I complete the mk7 euro taillight retrofit with the necessary wires and harnesses and coding to enable the rear fog lights, but install a euro headlight switch with an auto position, will I get an error every time I pass auto on the selector?

@Pineapple : Hi.

So, here's the thing about installing a EURO-switch = after fitment, you need to tell the 09 module how to control the new peripheral. The coding options for the EURO-switch are like this:

1. LDS_mit_AFL =LDS_with_AFL
2. LDS_mit_Nebel_Schlusslicht=LDS_with_fog_taillight
3. LDS_mit_Nebellicht=LDS_with_foglight
4. LDS_mit_Standlichtstellung=LDS_with_Parking Light Position

LDS= LichtDrehSchalter=Rotary Light Switch=EURO-switch
AFL = AssistenzFahrLicht= Adaptive Front Lighting=AUTO position

From a module coding perspectice, if you install the rear fog-light, but you don't have the Light-Sensor for the AUTO position - you will activate options 2, 3 and 4 (but NOT option 1)

From a wiring perspective - this is my guess of the EURO-switch set-up:

So again, if you do not have a light sensor for the new EURO-switch - you won't install the Purple wire on pin #2

Don

PS: I'm not sure if you are aware that eBay sells a version of the EURO-switch with a light-sensor that sits on the dashboard and plugs into the LDS connector. Of course it's very non-OEM and the operation of AUTO position is a tad clunky IMO - but I have installed the fake light-sensor on my test-bench - and it works . Maybe consider?

 

[Wizzi]

What the heck did i just find

https://www.aliexpress.com/item/100..._id=202412131426528115891688800500001503914_2

 

[DIB's]

@DIB's : hmm.......... no - the thermostat(s) on MQB platform cars use electronic devices because they are peripherals (meaning inputs) to the electronic control units(s). This means that the Engine Control Module (ECU) in this case needs to read the "value" of the thermostat and make a determination about what's happening to the coolant temperature.
((Snip lots of very helpful details))

Don

If I'm following correctly, mqb ecu is able to read temp data used to make various decisions, however the thermostat is not able to adjust when it opens or closes based on the ecu saying something like: "For best fuel economy let the engine warm up another 15*" and closing the thermostat a bit till achieving that goal?

 

[DV52]

If I'm following correctly, mqb ecu is able to read temp data used to make various decisions, however the thermostat is not able to adjust when it opens or closes based on the ecu saying something like: "For best fuel economy let the engine warm up another 15*" and closing the thermostat a bit till achieving that goal?

@DIB's : OK - I haven't described stuff properly (or the problem is my thick Aussie accent }. N82 is an actual valve - so it does "adjust" the flow of coolant. I haven't actually pull an N82 apart - so I guessing? Here's a picture of the valve (p/N #4H0121671D):

 

[DIB's]

Yeah, that looks like an adjustable t-stat.

For reference, my understanding of electronically adjustable t-stats is The Wife's bmw x1 which is perfectly happy to run the temps up or down as it feels necessary (as commanded by the ecu for whatever)

 

[Pineapple]

@Pineapple : Hi.

So, here's the thing about installing a EURO-switch = after fitment, you need to tell the 09 module how to control the new peripheral. The coding options for the EURO-switch are like this:

1. LDS_mit_AFL =LDS_with_AFL
2. LDS_mit_Nebel_Schlusslicht=LDS_with_fog_taillight
3. LDS_mit_Nebellicht=LDS_with_foglight
4. LDS_mit_Standlichtstellung=LDS_with_Parking Light Position

LDS= LichtDrehSchalter=Rotary Light Switch=EURO-switch
AFL = AssistenzFahrLicht= Adaptive Front Lighting=AUTO position

From a module coding perspectice, if you install the rear fog-light, but you don't have the Light-Sensor for the AUTO position - you will activate options 2, 3 and 4 (but NOT option 1)

From a wiring perspective - this is my guess of the EURO-switch set-up:

So again, if you do not have a light sensor for the new EURO-switch - you won't install the Purple wire on pin #2

Don

PS: I'm not sure if you are aware that eBay sells a version of the EURO-switch with a light-sensor that sits on the dashboard and plugs into the LDS connector. Of course it's very non-OEM and the operation of AUTO position is a tad clunky IMO - but I have installed the fake light-sensor on my test-bench - and it works . Maybe consider?

I appreciate the response! I think I follow the coding part, but the wiring is outside my foundation of knowledge. But it sounds like it doesn't take all too much to configure out the auto setting?

 

[cb1111]

I appreciate the response! I think I follow the coding part, but the wiring is outside my foundation of knowledge. But it sounds like it doesn't take all too much to configure out the auto setting?

I seem to remember doing this with my MkV and it was pretty straightforward. IIRC, I used Shadetree's ProDiag VAG tool for the PalmPilot to make the changes.

Back then, the PalmPilot was THE thing to have. I had a Kyocera 6035 that combined the Palm and the phone.

As far as a VAG tool, that couldn't be beat as you always had your tool with you and kept the cable in your glovebox. But I digress, the coding is simple.