Transmission kicks down, oil pressure light comes on w/engine fault, service now on 2009 Volkswagen Touareg TDI

Every time the transmission kicks down, the oil pressure light comes on w/ do not exceed 2,500rpm, engine fault, service now.
The codes P13D3, P13DC,P164B all came on. The 2 integrated cylinder pressure sensor glow plugs and Oil pressure switch were changed. What can be wrong now.
Please advise, Thanks.

1 answer
seek diag and est from a mech