Leaking urea/adblue system - P20F6 - P3052 - P249E

[Nego2403]

My friend took his car to a garage as he had emission control system error. They diagnosed it as a bad nozzle and replaced the part.

Right after returning from the garage he got the following faults.

Does the adblue system build up pressure when the ignition is turned on?

When I turned the ignition on it sounded like a pump was building pressure and druing that it sounded like something was leaking under the car and I could easily hear liquid splashing somewhere but there was no visible spot on the ground. I was thinking that they probably did not attach the pipe correctly to the nozzle and it therefore could leak.

I tried all tests for the emission control system and it can build pressure. During the bleeding of the urea system it fails probably because of a leak.
During driving I looked at the standard parameters for the denox system 1 and it showed a pressure of 5.5 bar and it constantly activated and deactivated the pump during driving.

Is there an easy way to test the pipes for leaks? I was considering lowering the tank and first checking the long pipe from the tank to the nozzle by creating a vacuum with my handheld vacuum pump. Is there other places where urea leaking could occur?

[RichardW]

Was the light on again, or did he just scan it on spec? They may be historic faults, I'd delete them and see if they stay away
Your description sounds like normal operation.

[Nego2403]

Was the light on again, or did he just scan it on spec? They may be historic faults, I'd delete them and see if they stay away
Your description sounds like normal operation.

The light was off when he left the garage. Right before arriving at his home the errors occurred. We could also confirm this based on the total distance covered. I reinitiliased the denox errors and cleared them. I also ran the replacement of the urea nozzle under repair. Let's see if the errors come back. At least I'm willing to help him with checking the piping if it returns.

The reason I'm thinking that there is an error is that the bleeding test failed when I did it which could be caused by a leak indeed.