Ok your talking about a Caddy. I've changed the title.
Manufacturer: VW, Date(s) Used: 05/2008-08/2010, Model: Caddy, Engine Code: BJB, 77Kw, 105PS, 1.9 Ltr, 4 Cyls, Remarks: Turbocharged Direct Injection Pumpe Düse (TDI-PD), 8v Timing belt
VAG Error Code: 16785/001025/4807/7337
EOBD II Error Code: P0401
Fault Location:
Exhaust Gas Recirculation (EGR) System - Insufficient Flow Detected
Possible Cause:
Malfunction Indicator Lamp (MIL)(K83) active.
Reduced Exhaust Gas Recirculation (EGR).
Reduced Power Output/Engine running rough.
Increased Emissions.
Wiring/Connector(s).
Hose leak/blockage.
Exhaust Gas Recirculation (EGR) Flow restricted/clogged.
Exhaust Gas Recirculation (EGR) Valve stuck closed/leaking/faulty.
Exhaust Gas Recirculation (EGR) System faulty.
Possible Solutions:
Check/Replace all faulty Wiring/Connector(s).
Check/Clean Exhaust Gas Recirculation (EGR) System.
Read Measuring Value Blocks (MVB).
Check/Replace Exhaust Gas Recirculation (EGR) Valve.
Control deviation < limit from map f (engine speed, desired airflow).
Special Notes:
When this fault is stored in a 2009-2012 North American Region (NAR) market
2.0L CR TDI (CBEA, CJAA, CKRA) VW Jetta/Golf (1K/AJ) or the NMS Passat (A3) chassis:
Please see: Technical Service Bulletin (TSB) 26-13-03 | Technical Product Information (TPI) #2031583/3 (formerly know as 26-12-08 | Technical Product Information (TPI) #2031583). When the Exhaust Valve Control Module (J883) is faulty, the engine controller may have any of the following Diagnostic Trouble Codes (DTCs):
P046F, P0477, P048A, P048B, P048C, P0401.
Some TDI-CR engines have a filter for the Exhaust Gas Recirculation (EGR) that can become restricted and cause a "Insufficient Flow" code.
When this fault is stored in a 2009-2014 North American Region (NAR) market
2.0L CR TDI (CBEA or CJAA ) VW Jetta/Golf (1K/AJ).
Please See Technical Product Information (TPI) 01 14 11 | #2034898
May also have fault code stored in Engine Control Module (ECM).
009315/P2463/009315 - Diesel Particulate Filter (DPF) - Excessive Soot Accumulation.
Restrictions in the Exhaust Gas Recirculation (EGR) Filter may occur after a regeneration, if the soot loads where high before the regeneration.
Tech Notes:
Exhaust Gas Recirculation (EGR) flow malfunction could be caused by a clogged Exhaust Gas Recirculation (EGR) valve or Exhaust Gas Recirculation (EGR) tube. Before replacing any parts try cleaning the Exhaust Gas Recirculation (EGR) valve, tube and passages.
When is the code detected?:
Restrictions in the EGR Filter may occur after a regeneration, if the soot loads where high before the regeneration.
VAG Error Code: 16683/15343/15343/14914/11226/12896/7384/5171/5671/000665
EOBD II Error Code: P0299
Fault Location:
Boost Pressure Regulation - Control Range Not Reached/Low Boost
Possible Cause:
Malfunction Indicator Lamp (MIL)(K83) active.
Reduced Power Output.
Limp Mode.
Limp mode: What is it, what are the causes, and how to fix it for the Audi and VW TDI diesel turbo.
Hoses/Pipes incorrectly connected, disconnected or leaking.
Charger Pressure Control defective.
Turbocharger faulty.
Diverter Valve faulty.
Possible Solutions:
Check Hoses/Pipes to/between Components.
Check/Clean/Replace Charge Pressure Control.
Check Turbocharger.
Check Diverter Valve.
Special Notes:
If the Turbocharger is faulty due to mechanical/internal problems or the exhaust system is restricted (typically the Catalyst) this fault may be the end result.
Gasoline:
When found in
2.0l TFSI:
Check Boost Pressure Control Valve (N249) (Turbocharger Recirculating Valve) for cracked rubber diaphragm. A new/optimized Valve is available under Part # 06H-145-710-D (or newer).
Rest of World (RoW) vehicles see: Technical Product Information (TPI) 2016331 for details.
North American Region (NAR) vehicles see: Technical Service Bulletin (TSB) 01-07-70 or 2013392 for details.
When stored in conjunction with misfire codes and/or fuel trim faults see the notes associated with the following faults regarding Positive Crankcase Ventilation (PCV) failure:
Crankcase Breather Valve
When found in
Audi A4/S4/RS4/Cabriolet (8K): 2.0l (CAEB):
See Technical Product Information (TPI) 2031245/6 - turbocharger excessive waste-gate play.
Diesel:
When found in VW Golf/Jetta (1K): 2.0l CR-TDI (CBEA/CJAA):
Verify the mechanical part of the Exhaust Valve Control Module (J883) is not seized or binding.
When found in the 1.9 L TDI-PD (BLS):
Check vacuum supply from the vacuum reservoir located in the valve cover for leaks. Using a vacuum gauge, wiggle the valve cover and hose connections to check for a leak. The following photo was submitted from a customer working on a 2010 VW Caddy (2K chassis) with this
vacuum reservoir problem.
As taken from my new
Free EOBD II Error Codes software