2006 Toyota Rav4 Diagnostic Trouble Code P2002

[pm dawn]

I bought this Toyota RAV4, 2006 model from a friend who returned from Germany in May 2013. It's Diesel, Manual and Turbocharged. A week ago after servicing (changed engine oil, fuel & engine oil filters) whilst driving, I realized the Check Engine (CEL), VSC and 4x4 system lights all came up the dashboard. I pulled up into a garage, the mechanic checked with his OBD tester and told me it has to do with a loose connector which he has resolved and has since cleared the codes.

The same day, the three guys (CEL, VSC & 4x4) came up again. The following day during my rounds in town, the lights went off the dashboard but I still went to see my mechanic. He again claimed to have cleared the codes. The day after, the guys (CEL, VSC & 4x4) came again and when I went to him he says the fault has to do with a part that he does not have currently. He however cleared the codes.

I requested for the Code which is P2002 - Particulate trap efficiency below threshold. After a lengthy search on WWW, I've come across a lot of factors including a DPF failure.

What could be the exact problem please? I need your pieces of advice please.

Thanks

BR