Egr p0400 issues

[Stephen2106]

I have a 2019 Toyota aygo 1.0 petrol 

I’m getting a p0400 fault code 

I’ve swapped the egr valve 

I’ve checked for air leaks 

no carbon build up 

if I clear the fault it drives fine but i find that taking my foot off the gas pedal for around 3-5 seconds it will bring the fault back up, 

I’ve also tried a different throttle body and air flow sensor but no different 

[martswain]

If you are in the UK why are you bothering to do anything yourself ?

A 2019 vehicle will have a 5 year Toyota warranty.

[flash22]

Throwing parts at it, isn't a good idea, unless it's high mileage it shouldn't be sooted/coked up, but the most common place is where the egr tube from the cat meets the head

I wouldn't rule out an iffy map sensor

[Stephen2106]

5 hours ago, flash22 said:

Throwing parts at it, isn't a good idea, unless it's high mileage it shouldn't be sooted/coked up, but the most common place is where the egr tube from the cat meets the head

I wouldn't rule out an iffy map 

[Stephen2106]

I have a identical aygo that has no issues so I have been trying the parts off that one,

I’ve sprayed clutch and brake fluid on the air lines 

swapped map sensor

swapped throttle body 

swapped egr valve 

I was wondering if egr needs re learning, 

I can get the p0400 to come on by driving the car and taking my foot off the throttle for 3-5 seconds 

toyota won’t look at it as it is a damaged repaired car 😞 

is there anything else I can try before I get it mapped out 

 

[TonyHSD]

You can check after egr the pipe where goes into the intake and the intake manifold itself. Remove these and clean thoroughly. If everything along the egr up to the intake it’s  clean but air passages blocked inside the intake like on Prius for example you will still have trouble. No idea how Aygo system looks like but as an idea where else to look at. 
Good luck 

[Stephen2106]

The air intake on the aygo is like a fixed manifold on the back of the engine this is where the map sensor goes, I’ve checked it all and it is clean, 

the car has only covered 15,000 miles 

and is a 1.0 petrol so no carbon build up 

[flash22]

2018 onwards have quite a few changes both electrical and mechanical

does it do it after 3 throttle snaps ? Are there any other codes present

P0400 is a 3 trip code, the criteria for the code is the MAP does not match the set values

 

[flash22]

it may just need a relearn, disconnect the Battery for 15-20 mins and reconnect it

If the car has had a heavy is front end damage check the exhaust for damage especially the EGR tube from the cat

[Stephen2106]

It comes up as a pending fault 

on my diag I have it plugged in while driving 

just the p0400 code 

I will disconnect the Battery and try that 🤞