How to fix P0238 Manifold Pressure/Boost Sensor (G31) Signal too High-wiring issue Octavia Mk II

P0238 Turbocharger boost Sensor (A) Circuit High.

I connected my Autel diagnostic tablet and scaned the car for the error codes.
The P0238 Turbocharger boost Sensor (A) Circuit High input was showed as active error code.
The other two errors occurred because the Mass Air flow Sensor was disconnected.

Watch my youtube video for more detailed steps.

Tools used in this video:

Autel MaxiCOM MK808

Mustool MT8206

Needle Back Test Probe Pin

Back Probe Kit Alligator Clip to 4mm Banana Plug


I checked the live data and noticed that the actual pressure was much higher than the required pressure value.

The owner said he had already changed the G31 sensor.

The sensor has 4 wires:

1 – Ground,

2 – NTC resistor (temperature signal),

3 – 5 volts from ECU,

4 – Boost pressure signal.

According to the diagram, the wires from the G31 sensor are connected to the ECU through the T14 pins connector, pin 8 and 10.

I checked the continuity of the wires according to the color of each one:
– the purple wire, has no continuity to the connector
– grey / black, had continuity to the connector
– the yellow wire, had continuity to the connector
– brown, also had continuity to the connector


I picked up the wires and noticed a green area where the wires touched the antifreeze hose.
The purple and grey/black wires are broken, and a few more wires were about to break.

I repaired the wires and I rechecked the live data in the diagnostic tablet, the required pressure is almost the same with the measured one.


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