P0627 Error Code

[Yooj]

Hi,

I have a 2010 Tiguan 2.0 tdi with a CBAB engine.

I recently got an error code 'P0627' which caused an engine light and caused the car to go into limp mode.

I initially tried to reset the code, and it came straight back.

The code is described as: P0627 Fuel Pump A Control Circuit /Open

So a bit of googling led me to think that the likely culprit would be the control module for the in-tank low pressure fuel pump.

Searching on-line indicated that the control module is likely tucked up under the bodywork within the hatch of the fuel pump under the rear seat.

So this is where my problem occurs... there is no control module. I have looked everywhere, and for the life of me I cannot find one. Furthermore, there doesn't appear to be any wiring coming off of the pump connector which would go to the controller. There is just 5 wires, and these wires go back towards the front of the car.

So my question is whether there is one, but it is elsewhere on the car, or that this particular engine-type does not have a module?

And if it does, then where could it be?

And if it doesn't, then is it likely the fault is on the pump itself?

(I would add a picture, but I cannot see the option)

Thanks,

Yooj

[Yooj]

So I have done some more investigation and the issue is heat related. I noticed that when the ambient air temperature was greater than 28 deg C, and the inside of the cabin was really warm then I would get the fault. Also, when I had the fault and I then ran the car with the a/c on for enough time to cool the cabin, then the fault would reset after cycling the ignition.

Therefore, I reckoned that this pointed towards electrical.

Also, I still couldn't find a pump controller, so I reckon that the issue was likely relay related.

So I ordered a new 449 relay, and swapped out the relay in position 6 on the relay board behind the dash.

Today was a reasonably hot day, and the issue did not present itself, and therefore, hopefully the relay was the issue.

Yooj