Help with VCDS error - amber coil and limp mode.

[njsb14]

Hi

Driving home from work today, doing approx 70mph on motorway, accelerated and amber coil illuminates, drop in power and engine fault - Workshop error on display.
Pulled over, visual check of engine, all looks OK, turn off engine, restart car clears error.
Drove again OK for 10 miles, came to lights, accelerated away at approx 70mph, same issue, pull over restart all OK.
Drove again OK for 20 miles, came to hill when hit 70mph, same issue, pull over restart all OK.

When got home connect up VCDS and have the following listed;

1 Fault Found:
7385 - Boost Pressure Regulation
P0234 00 [096] - Limit Exceeded (Overboost Condition)
Intermittent - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 3
Mileage: 154302 km
Date: 2016.01.02
Time: 18:03:23


Car: Golf Mk6, 1.6TDi SE

Any ideas where to start?

Thanks

[Keithuk]

VAG Error Code: 16618/000564
EOBD II Error Code: P0234

Fault Location:
Boost Pressure - Regulation Limit Exceeded (Overboost Condition)

Possible Cause:
Malfunction Indicator Lamp (MIL)(K83) active.
Boost Pressure too high.
Reduced Power Output.

Hoses
incorrectly connected, disconnected, blocked or leaking.
Charge Pressure Control Solenoid Valve (N75) faulty.
Manifold Pressure/Boost Sensor (G31) faulty.
Turbocharger stuck/faulty.

Possible Solutions:
Check Charge Pressure Control System.
Read Measuring Value Blocks (MVB).
Perform Output Test (to check the Turbocharger).
Perform Basic Setting (to check the Charge Pressure Control).
Difference of set value boost pressure vs. altitude sensor signal > 200 - 1275 hPa.
Perform Pressure Test to locate Leaks.
Check/Replace Charge Pressure Control Solenoid Valve (N75).
Check/Replace Manifold Pressure/Boost Sensor (G31).
Check/Replace Turbocharger.

Description:
The boost pressure sensor responds to pressure changes in the intake manifold. This pressure is created by the turbocharger and changes with accelerator pedal position (APP) and engine speed. The Engine Control Module (ECM) uses this information to assist in diagnosis of the barometric pressure (BARO) sensor and to provide engine overboost protection. The boost pressure sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. The Engine Control [Module (ECM) supplies 5 volts to the boost pressure sensor on the 5-volt reference 2 circuit, and provides a ground on a low reference circuit. The boost pressure sensor provides a signal to the Engine Control Module (ECM) on a signal circuit relative to the pressure changes. The Engine Control Module (ECM) monitors the boost pressure sensor signal for voltage outside of the normal range. The Engine Control Module (ECM) calculates a predicted value for the boost pressure sensor. The Engine Control Module (ECM) then compares the predicted value to the actual signal.

As taken from my new EOBD II Fault Codes software