Checking signal wire

• Disconnect harness connector at charge air pressure sensor.
• Connect multimeter to socket 101 and socket 108 of test box for voltage measurement.
• Start engine and run at idle.
  • Specification: about 1.90 V
• Bring engine to RPM by depressing pedal suddenly.
  • Specification: approx. 2.00 - 3.00 V

If specified values are not obtained:

• Check following wire connection for open circuit and short circuit to Ground (GND) and B+:
  CHARGE AIR PRESSURE SENSOR HARNESS CONNECTOR TERMINAL SPECIFICATIONS
  
  

  Harness connector terminal	VAG 1598/31 or test box Bushing
  4	101

• Repair open circuit or short circuit if necessary.
  Fig 1: Identifying Charge Air Pressure Sensor Harness Connector Terminals

  Courtesy of AUDI OF AMERICA, INC.

  If wire connection is OK:

• Replace charge air pressure sensor -G31-.