EGR issues since new turbo fitted

[bigGfaefife]

Hi Folks, reaching out for your help with my 2008 Avensis D4D 2.0L estate which has done nearly 200,000miles without a hitch, but since my local garage fitted a new turbo a few months back, I have had issues. So immediately after fitting the turbo, two fault codes came on, 1 was P0400 for EGR valve issue, and the other was that a software update was required. The garage put it into an autoelectrics shop for diagnostics and they said the software update was due to the turbo being a variable vein turbo and the EGR valve was faulty (although no fault prior to the turbo being fitted). The garage got someone in with a laptop to update the software, and they fitted a new EGR valve. Since then, the P0400 code keeps coming back. The garage replaced the EGR valve a second time, cleaned out all the pipes/inlet manifold etc but after about 10-15miles, the fault comes back. The garage have now adnitted they have no idea, so I looked at it myself, cleaned up the valve etc again, cleared the fault code, ran it up to temp and it was fine, but again after about 15miles the fault code comes back. I can't see any issue with the vacuum hose, and if I reset the fault code and run the car with the pipe off to the valve, it operates ok up to 150 degrees but then the fault code comes back. My suspicion is that there is nothing wrong with the whole EGR part, and that the problem is over fueling since the new turbo was fitted, as the carbon build up on the EGR valve seems too great for the short period of time. I don't have a manual for the car(although any suggestions on where i could get one would be great) but I am sure i have located the temp sensor for the valve and it seems to be operating ok and not suffering from huge carbon build up either. The final thing to note is that when the P0400 code is on, the car runs reallly erratically at 1500rpm, but other than that it runs great. HELP!!!

[2009joe]

7 hours ago, bigGfaefife said:

Hi Folks, reaching out for your help with my 2008 Avensis D4D 2.0L estate which has done nearly 200,000miles without a hitch, but since my local garage fitted a new turbo a few months back, I have had issues. So immediately after fitting the turbo, two fault codes came on, 1 was P0400 for EGR valve issue, and the other was that a software update was required. The garage put it into an autoelectrics shop for diagnostics and they said the software update was due to the turbo being a variable vein turbo and the EGR valve was faulty (although no fault prior to the turbo being fitted). The garage got someone in with a laptop to update the software, and they fitted a new EGR valve. Since then, the P0400 code keeps coming back. The garage replaced the EGR valve a second time, cleaned out all the pipes/inlet manifold etc but after about 10-15miles, the fault comes back. The garage have now adnitted they have no idea, so I looked at it myself, cleaned up the valve etc again, cleared the fault code, ran it up to temp and it was fine, but again after about 15miles the fault code comes back. I can't see any issue with the vacuum hose, and if I reset the fault code and run the car with the pipe off to the valve, it operates ok up to 150 degrees but then the fault code comes back. My suspicion is that there is nothing wrong with the whole EGR part, and that the problem is over fueling since the new turbo was fitted, as the carbon build up on the EGR valve seems too great for the short period of time. I don't have a manual for the car(although any suggestions on where i could get one would be great) but I am sure i have located the temp sensor for the valve and it seems to be operating ok and not suffering from huge carbon build up either. The final thing to note is that when the P0400 code is on, the car runs reallly erratically at 1500rpm, but other than that it runs great. HELP!!!

boss think maybe only way is to map it out if getting expensive problems map out egr and and do a fuel mod 2 

[Devon Aygo]

DTC    P0400    Exhaust Gas Recirculation Flow

DESCRIPTION

The EGR system recirculates exhaust gases, in order to suit every driving condition. The recirculated gas mingles with the intake air, therefore the EGR system can slow combustion speed and keep the combustion temperature down. This helps reduce NOx emission.
In order to increase EGR circulation efficiency, the ECM adjusts the lift amount of the EGR valve and intake shutter valve angle (throttle valve).

MONITOR DESCRIPTION

1. If the EGR valve is forcibly operated but the intake air amount does not vary, the ECM determines that the EGR valve is malfunctioning. The ECM then illuminates the MIL.
2. When the target and actual positions of the EGR valve are different, the ECM interprets this as a malfunction of the EGR valve and illuminates the MIL.

It may just be coincidence that the EGR issues have started since the new Turbo also consider the EGR circuit is much more than just one valve, the intake manifold & ports into the engine also need cleaning as well as follow the EGR circuit back ensuring no blockage/restriction, beware the EGR cooler is a massive 7-10 hour job in a workshop let alone on the kerb side.

 

[bigGfaefife]

Devon Aygo - Thanks, it may be a coincidence, but I suspect not. The whole route of the EGR gases have been cleaned several times including inlet manifold etc. I suspect there is some difference between the fuel mapping from the original turbo and the new one, so as 2009Joe says, mapping may be the answer (or mapping out )