UK-POLOS.NET - THE VW Polo Forum

I was out of town when I turned on the engine and the good old mighty check engine light came on. Lovely.

I was nowhere close to home and the car seemed to be fine so I prayed to the VW gods for the problem to not be anything drastic and started driving.

I got home and went straight to my friend that has a vcds cable, scanned the car for error codes and the P261A00 coolant pump 2 error showed. I think this is the secondary coolant pump, but I'm not sure where it's located so I can take a look at it.

Also can something brake if I keep driving the car around town with this problem? I am not a mechanic so I don't have a clue what's the role of this secondary pump. I've drove it 60 miles with no issues so I guess this is an intermittent problem.

It would be better for the engine if you replaced this pump if it has failed, I'm not sure which section of the engine and charge cooler it works with, if it was only the charge cooler it would not be such a problem as it would only limit the engine's output power.

It is, on my wife's 6C Polo 2015 1.2TSI, on the front of the engine and probably has maybe 3 pipes connected to it (or 2) and it has a black plastic body and obviously a power connector, possibly tied/connected to the engine block with a thin metal bracket.

I am going to replace it of course. I was just curious if I can take the car for a 5 min drive to the market.

While I was driving I didn't notice any drop in power. Car felt the same as it did before.

Can the auxiliary pump be tested via vcds with an output test or something?

I managed to switch the pump on in my wife's 2015 6C Polo 1.2TSI, if you switch it on, and it will only run that test for a few minutes, at least in my wife's 6C Polo 1.2TSI, I could hear it and see coolant being returned to the coolant reservoir via the small pipe on the coolant reservoir.

Edit:- I used "output test" in ENGINE.

yeah they do fail from time to time. it's easy to reach! it's next to the right hand side drive shaft. 3 bolts (replace the bolts too) and two hose clamps.

that's great!
I'll take a look tomorrow to make sure the plug is well seated. I had the timing belt and the main water pump changed a week ago and maybe they had to unplug the aux water pump and forgot to plug it back in. Worst case I'll just order a new one. I don't think they are that expensive(maybe 50 euro or something around there)

Today I decided to finally check that aux coolant pump. Got under the car made sure the connector was well seated and started the Output Test for the pump.

It started intermittently buzzing (but I think that's just how the output test works) and I tried to feel if water was going through the pipes. Couldn't really tell if the vibrations came from the pump or the water going through the pipes.

I did a quick google search and found that a high pitched buzzing sound from under the dashboard could be a sign of a bad aux coolant pump. I do actually get an intermittent buzzing sound from under the right part of the dashboard, but I thought It was the fan from the AC. I turned the AC off and the sound was still there. The buzzing seems to get faster the faster the engine is revving.

I think I'll have to order a new aux pump after all.

I think that on the 2015 VW Polo 1.2TSI engine, that pump runs at maybe 3 different speeds, and VCDS operates it using all maybe 3 speeds for a short period in the test, and it did sound like an electric pump running and not just buzzing - if that helps at all.

Edit:- on that 1.2TSI car, that pump forces coolant back into the reservoir by the small pipe at the top, if your pump is plumed in in a similar way, it should also force coolant back into the reservoir - maybe @iichel could confirm if that is true on his car.

Mine sounded just like a phone buzzing. Like it was trying to spin but couldn't. I tried tapping it a bit to see if something changes, but it seems to be the same. I'll ask a mechanic friend of mine to check it out as well, but I'm pretty sure it's stuck. At least it's not an expensive part

Can you see the flow rate via live value?

amer6R wrote: Sat Sep 04, 2021 8:07 pm Can you see the flow rate via live value?

I'm not sure how to do that tbh. I'll try tomorrow morning to look for it.

the coolant pump on the 1.2 TDI will pump towards the EGR cooler

iichel wrote: Sun Sep 05, 2021 9:07 am the coolant pump on the 1.2 TDI will pump towards the EGR cooler

But does that pump end up returning coolant to the reservoir via the small coolant return pipe?

I was asking that just in case it makes life easier for the OP as checking for that while commanding the pump to run would give a very good answer to "is the electric coolant pump working properly?".

Unfortunately in my 2011 Audi S4, the electric coolant pump just circulates water around the charge cooler/charge cooler radiator water loop without returning it via the reservoir - which initially caused me concerns when I commanded that pump to run prior to replacing the coolant, I initially assumed "no returning flow via the reservoir" meant that that electric pump while sounding it was okay, was in fact not working correctly - I was wrong!

No, in fact it will pump towards the cold exit of the main radiator:

Finally got my mechanic friend to take a look at the pump.

First thing he said was 'Let me tap it a bit to see if I can get it to run again'. I said that I already hit it a few times and didn't really see an improvement, but he wanted to try as well and I wasn't going to stop him. He tapped the pump for a min or two while I ran the Output Test and he stops and goes:

'I don't really get what problem you are having, I can feel the coolant flow through the pipes' to which I reply 'What do you mean I already checked that there wasn't any coolant flowing' so I go and see for myself and lo and behold there was coolant flowing. Not only that but the pump buzzing sound changed from 'phone buzzing' to 'coolant pump pumping coolant'.
*visible confusion*

So I guess if something breaks on your car, just hit it until it starts working again.