Turbo Boost Sensor: Testing and Inspection

Charge air pressure sensor-G31-, checking





Special tools, workshop equipment, test and measuring appliances and aux. items required
^ V.A.G 1526 A Hand multimeter
^ V.A.G 1594A Adapter set
^ V.A.G 1598/31 Test box
^ Wiring diagram

Check conditions
^ On Board Diagnostic (OBD) has detected a fault with the charge air pressure sensor.
^ Ignition switched off.

Checking voltage supply and wiring to control module





- Pull 4-pin connector--2-off charge air pressure sender-G31-1-.





- Connect multimeter to measure voltage to contacts 1 (Ground) and 3 (positive) of connector for charge air pressure sensor using adapter cables from V.A.G 1594 .
- Switch on ignition. Specification: min. 4.5 V
- Switch off ignition.

If no voltage is present:





- Connect test box V.A.G 1598/31 to control module wiring harness. The engine control module remains disconnected.





- Check wiring between test box and connector for open circuit according to wiring diagram.
Contact 1 + socket 108
Contact 3 + socket 98
Contact 4 + socket 101
Wire resistance: Max. 1.5 ohms
- Additionally check wires for short to one another.
If no wiring fault is detected and voltage was present between contacts 1+3:
- Checking the functions
If no wiring fault is detected and no voltage was present between contacts 1+3:
- Replace engine control module.

Checking function
- Connect the test box V.A.G 1593/31 to engine control module wiring harness and to engine control module.
- Reconnect connector to charge air pressure sensor (G31).
- Connect multimeter to measure voltage to sockets 101 (positive) and 108 (Ground) using adapter cables from V.A.G 1594.
- Start engine and measure the basic voltage. Specification: 1.80 to 2.00 V
- Raise engine revs by pressing accelerator to Specification: 2.00 to 3.00 V

If the specifications are not attained:
- Replace charge air pressure sensor (G31).
- Check DTC memory.
- Read out readiness code.
- If the DTC memory has been erased or the engine control module separated from the permanent positive, the readiness code must be generated again.