Turbo Boost Sensor: Testing and Inspection

Diagnostic Procedures

Charge Air Pressure Sensor, Checking

• Cylinder bank 1 is located in direction of travel, right.

• Cylinder bank 2 is located in direction of travel, left.

• Use only gold-plated terminals when servicing terminals in harness connector.

Special tools, testers and auxiliary items required

• Multimeter (VAG1526) or Multimeter (VAG1715)

• Turbocharger tester (VAG1397A)

• Connector test kit (VAG1594)

• Wiring diagram

Test Prerequisites

• Fuses in E-box (plenum chamber, left) must be OK:

• Battery voltage must be at least 11.5 volts.

• All electrical consumers such as, for example, lights and rear window defroster must be switched off.

• For vehicles with automatic transmission, selector lever must be in P.

• If vehicle is equipped with an A/C system, it must be switched off.

• Ground (GND) connections between engine and chassis must be OK.

Cylinder bank 1: Check Charge Air Pressure Sensor (G31).

Cylinder bank 2: Check Charge Air Pressure Sensor 2 (G447).

Charge Air Pressure Sensor (G31) Test Sequence

- Connect diagnostic tester.

- Switch ignition on.

- Under address word 33, select "Diagnostic mode 1: Check measured values."

- Select the measuring value "PID 11: Manifold Absolute Pressure (MAP)".

- Compare the Manifold Absolute Pressure (MAP) displayed on the diagnostic tester and the display on turbocharger tester (VAG1397/A) with each other.

Specified value: The pressures must match

(Tolerance ± 50 mbar or 5 kPaA)

• The turbocharger tester is required to obtain an independent comparison value. Turbocharger tester must be set to measuring range I (absolute pressure). A barometer can also be used in its place.

• Manifold Absolute Pressure (MAP) is displayed in kPaA on the diagnostic tester, in mbar on the turbocharger tester

Conversion: 1 mbar = 0.1 kPaA.

If specified value is not obtained:

- End diagnosis and switch ignition off.

- Control Module Wires, Checking.

Control Module Wires, Checking

- Disconnect 4-pin connector from Charge Air Pressure Sensor (G31) with Intake Air Temperature (IAT) Sensor (G42) (- A -).

- Connect test box ((VAG1598/42)) to Engine Control Module (ECM) (J623) wiring harness using adapter cable ((VAG1598/39-2)) , connecting test box for wiring test.

- Check wires between test box and connector for open circuit according to wiring diagram.

Terminal 3 + socket 62

Terminal 4 + socket 78

Wire resistance: max. 1.5ohms

- Also check wires for short circuit to each other, to vehicle Ground (GND) and to B+.

Specified value: infinite ohms

If no malfunctions are found in wires:

- Replace Charge Air Pressure Sensor (G31) with Intake Air Temperature (IAT) Sensor (G42).

- Erase DTC memory of Engine Control Module (ECM) --> [ Diagnostic Mode 04 - Erase DTC Memory ] , Diagnostic mode 4: Reset/erase diagnostic data.

- Generate readiness code --> [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.

Charge Air Pressure Sensor 2 (G447) Test Sequence

- Connect diagnostic tester.

- Switch ignition on.

- Under address word 33, select "Diagnostic mode 1: Check measured values."

- Select the measuring value "PID 11: Manifold Absolute Pressure (MAP)".

- Compare the Manifold Absolute Pressure (MAP) displayed on the diagnostic tester and the display on turbocharger tester (VAG1397/A) with each other.

Specified value: The pressures must match

(Tolerance ± 50 mbar or 5 kPaA)

• The turbocharger tester is required to obtain an independent comparison value. Turbocharger tester must be set to measuring range I (absolute pressure). A barometer can also be used in its place.

• Manifold Absolute Pressure (MAP) is displayed in kPaA on the diagnostic tester, in mbar on the turbocharger tester

Conversion: 1 mbar = 0.1 kPaA.

If specified value is not obtained:

- End diagnosis and switch ignition off.

- Control Module Wires, Checking.

Control Module Wires, Checking

- Disconnect 4-pin connector from Charge Air Pressure Sensor 2 (G447) with Intake Air Temperature (IAT) Sensor 2 (G299) (- B -).

- Connect test box ((VAG1598/42)) to Engine Control Module 2 (J624) wiring harness using adapter cable ((VAG1598/39-2)) , connecting test box for wiring test.

- Check wires between test box and connector for open circuit according to wiring diagram.