GOLFMK8
GOLFMK7
GOLFMK6
GOLFMKV

P1927 Auxiliary water pump relay ?

Ash17

New member
My OBDeleven shows engine code P1927 "Auxiliary engine coolant pump relay". Does this mean the auxiliary pump is going bad or is it just something electrical like a fuse ?
There's oil on the auxiliary pump and the sensor from a timing cover leak I'm repairing, could that effect the sensor or the internals of the pump it self and cause this code ?
 

Allchokedup

Autocross Champion
My OBDeleven shows engine code P1927 "Auxiliary engine coolant pump relay". Does this mean the auxiliary pump is going bad or is it just something electrical like a fuse ?
There's oil on the auxiliary pump and the sensor from a timing cover leak I'm repairing, could that effect the sensor or the internals of the pump it self and cause this code ?
My aux pump has been leaking for 2 years now. Everytime it gets warm out it leaves a puddle on the ground.
I have yet to get a CEL.
are you sure the pump is coming on once car is shut off? I would guess it's not and there is no power going to it because of a bad relay :)
 

Ash17

New member
My aux pump has been leaking for 2 years now. Everytime it gets warm out it leaves a puddle on the ground.
I have yet to get a CEL.
are you sure the pump is coming on once car is shut off? I would guess it's not and there is no power going to it because of a bad relay :)
I got a fault code P2015 for the intake manifold runner flap at the same time as this P1927 code for the auxiliary coolant pump. Currently I'm replacing the old tensioner in it as well as carbon cleaning since I had to replace the intake manifold, so I can't start it up, do you have any information on which relay controls the auxiliary pump ? I've done some work on my car before but never anything electrical so I'm a bit lost on how to troubleshoot these things, thanks!
 

Attachments

  • Screenshot_20210403-185659_OBDeleven.jpg
    Screenshot_20210403-185659_OBDeleven.jpg
    345.5 KB · Views: 7

Allchokedup

Autocross Champion
I got a fault code P2015 for the intake manifold runner flap at the same time as this P1927 code for the auxiliary coolant pump. Currently I'm replacing the old tensioner in it as well as carbon cleaning since I had to replace the intake manifold, so I can't start it up, do you have any information on which relay controls the auxiliary pump ? I've done some work on my car before but never anything electrical so I'm a bit lost on how to troubleshoot these things, thanks!
Maybe this will help. Do you have a multimeter to test circuits? I would start by checking the fuses that say aux pump fuse. This system is a bit strange and complex. I think fans have to come on first for the aux pump to come on.
Nevermind all that, just set your meter on continuity and check the fuses. When you touch the leads together it should beep? Yes? Ok now on top of each fuse there are 2 little spots. Stick each lead to the spots see if it beeps. Yes? The fuse is good.
A relay is a bit more complicated. You would need to put 12v power to it to test it. If fuses are good I would just get a new relay.
You can take the aux pump off and put 12v power to it and see if it comes on, that would eliminate the pump being bad
 

Attachments

  • Screenshot_20210502-213611_Chrome.jpg
    Screenshot_20210502-213611_Chrome.jpg
    772.4 KB · Views: 9
  • Screenshot_20210502-213636_Chrome.jpg
    Screenshot_20210502-213636_Chrome.jpg
    232.1 KB · Views: 9
  • Screenshot_20210502-213646_Chrome.jpg
    Screenshot_20210502-213646_Chrome.jpg
    223.7 KB · Views: 9

Ash17

New member
Thank you for the input but unfortunately my fuse box is different from the one in the diagram you attached. I have a 2010 mk6 gti and I cant seem to find any diagram that accurately resembles mine. Do you have any suggestions ?
 

Attachments

  • 16200170961655005888310159660657.jpg
    16200170961655005888310159660657.jpg
    2.3 MB · Views: 11

Allchokedup

Autocross Champion
This looks correct, here is the link.
Like I said previously, it's really easy to check fuses with a test light/multimeter. Let me know if you dont know how?
I would start with fuses then relays. Is the car put together and running at the moment? How do you know aux pump.isnt working?
 

Attachments

  • Screenshot_20210503-080716_Chrome.jpg
    Screenshot_20210503-080716_Chrome.jpg
    378 KB · Views: 6

Ash17

New member
This looks correct, here is the link.
Like I said previously, it's really easy to check fuses with a test light/multimeter. Let me know if you dont know how?
I would start with fuses then relays. Is the car put together and running at the moment? How do you know aux pump.isnt working?
I won't be able to start the car for a couple more days untill I'm done with the manifold and timing components. My only clue that something is problematic with the aux pump is from the P1927 auxiliary coolant pump relay open circuit code my OBDeleven showed when I also had the P2015 for the runner position sensor. Both popped up at the same time when I started my car at lunch one day and I haven't driven it since. Both the water pump and aux pump were replaced by a shop about a year ago and my only other insight is that I definitely see a bit of oil residue around the aux pump and connector and I know the oil + electrical connector must not = good, right ? Only fuse I could tell from that second diagram you attached that might be for the aux pump was F11 labeled Auxiliary heater but still uncertain if that's it ? And there's also not even a fuse in the location in my car all though that diagram layout does look identical to mine. Is the aux pump fuse/relay possibly grouped under another fuse/relay on that diagram? I was using the legend "since 2009" as my car is a 2010. Thank you so much for all your help so far by the way.
 

Ash17

New member
I've seen a couple youtube vids and it seems pretty straight forward on the process it self but a couple things to note, I haven't purchased/used a multimeter yet (but could get one relatively easily) and I don't know what to set it too or what numbers to look for when testing fuses/relays. I know that you need a power source with little alligator clips when testing relays but my knowledge on car electronics and how to troubleshoot them is about zero.
 

Allchokedup

Autocross Champion
Go get a cheap one make sure it has continuity tester. That is an audible beep when you touch the leads together.
You can also just get a cheap test light but that's a little bit more involved. I will make u a vid when I get home later
 

Ash17

New member
Go get a cheap one make sure it has continuity tester. That is an audible beep when you touch the leads together.
You can also just get a cheap test light but that's a little bit more involved. I will make u a vid when I get home later
You rock dude ! I'll pick one up after work today, so grateful for people like you on this forum that interact with small posts and offer genuine help ✌.
 

Allchokedup

Autocross Champion
Ok, pretty simple. This is how you test a fuse. There are 2 little openings on each fuse.
https://youtube.com/shorts/VB2R30Uyg64?feature=share
As for the relay..the one I have pictured here numbers 85 and 86 would be your control wires. You would put power to 85 and ground 86. When you put power to those terminals as described 87 and 30 are the circuit that would close. See the little arm ? That means it closes, in the picture it's showing the circuit is open which would make this a normally open relay. Putting power to 85 and grounding 86 will cause the relay to close and then 87-30 would be a closed circuit. You can test by using continuity tester like you tested the fuses. If your relay has more than 4 terminals that's another issue all together and you will have to learn to read the schematic.
 

Attachments

  • 20210503_183100.jpg
    20210503_183100.jpg
    1.3 MB · Views: 8

Ash17

New member
Ok, pretty simple. This is how you test a fuse. There are 2 little openings on each fuse.
https://youtube.com/shorts/VB2R30Uyg64?feature=share
As for the relay..the one I have pictured here numbers 85 and 86 would be your control wires. You would put power to 85 and ground 86. When you put power to those terminals as described 87 and 30 are the circuit that would close. See the little arm ? That means it closes, in the picture it's showing the circuit is open which would make this a normally open relay. Putting power to 85 and grounding 86 will cause the relay to close and then 87-30 would be a closed circuit. You can test by using continuity tester like you tested the fuses. If your relay has more than 4 terminals that's another issue all together and you will have to learn to read the schematic.
Right on man great info there, matches up with some of the vids I've been seeing. Appreciate the effort, all I gotta do is figure out which fuse is associated with the aux pump. I've heard it might be tied in with the fan control module🤔
 

Allchokedup

Autocross Champion
Right on man great info there, matches up with some of the vids I've been seeing. Appreciate the effort, all I gotta do is figure out which fuse is associated with the aux pump. I've heard it might be tied in with the fan control module🤔
Yea, like I said it's a complicated circuit.
You can however check every fuse pretty quickly using your meter. If all fuses check out I would just replace the relay/relays. I'm sure you can scoop one up at local auto store(as long as Gavin Newsome isn't watching)
;)
 
Top