EGR higher than desired
Check the VGT and the EGR valve. Check for leakages in the gas exchange system. Check the MAF sensor Check the MAP/ boost pressure sensor Check the Boost temperature sensor Check the Exhaust pressure sensor For Eu5 vehicles: After repair run the " Checking the EGR system for devalidation of fault codes" . If the performance test could not finish for some reason, use the opportunity to erase NOx control DTC:s For Eu6 vehicles: After repair run the workshop test for adaptation of MAF or " Checking the EGR system for devalidation of fault codes".
What you'll see
No driver-visible symptom recorded.
System reaction
Engine performance may be degraded due to excessively high levels of EGR.
Diagnostic depth
The requested amount of EGR is higher than desired. Test conditions: Massflow sensor must be adapted and fuel injection must be higher than min limit.
The control of the EGR is not working properly. Possible faults are: VGT stuck in closed position. EGR valve stuck open. Leakage in the gas exchange system MAF defective MAP/ Boost pressure sensor defective Boost temperature sensor defective Exhaust pressure sensor defective