Boost Pressure Regulation, Checking

Boost Pressure Regulation, Checking

Recommended special tools and equipment e.g.:







- V.A.G 1397 A Turbocharger Tester

Test requirements
- No leaks on intake or exhaust side.
- Coolant temperature must be at least 80 degrees C. Diagnostic mode 1: Check measured values; PID 5, Coolant temperature. Diagnostic Mode 1: Check Measured Values

Test sequence
- Charge pressure is measured under Wide Open Throttle (WOT) while driving or on the roller type test stand.

Observe the safety precautions that apply to road tests.







- Disconnect connection hose between intake manifold and fuel pressure regulator at intake manifold and connect to T-piece of turbocharger tester (V.A.G1397A).
- Switch on measurement range I.

NOTE:
- Using Turbocharger Compression Tester.
- The hoses must be connected absolutely free of leaks.
- When charge pressure is measured during the drive, a second person is necessary to operate the turbocharger tester for safety reasons.
- Make sure that the pressure hose is not pinched between engine hood and chassis.

- Measure charge pressure at Wide Open Throttle (WOT):

On dynamometer
In 3rd gear or in 2nd drive mode

While driving
Vehicles with manual transmission
- Accelerate vehicle from slow speed to Wide Open Throttle (WOT) while in 3rd gear.

Vehicles with automatic transmission
- Manually place vehicle in 4th gear and accelerate vehicle from low speed at Wide Open Throttle (without kick down, transmission does not downshift any more).

Engine code APH
- At 3000 RPM, press the "M" memory button on turbocharger tester and read out the test value.

Specified value: (absolute pressure)1.300 to 1.750 bar

Engine code AWP
- Between 1800 to 2300 RPM, press the "M" memory button on turbocharger tester and read out the test value.

Specified value: (absolute pressure) 1.350 to 2.000 bar

Engine code AWV
- Between 1800 to 2300 RPM, press the "M" memory button on turbocharger tester and read out the test value.

Specified value: (absolute pressure) 1.350 to 1.750 bar

Engine code BKF, BNU
- At 3000 RPM, press the "M" memory button on turbocharger tester and read out the test value.

Specified value: (absolute pressure) 1.500 to 1.650 bar

Continue for all vehicles

NOTE: Repeat measurement if boost pressure was not fully charged or if the difference between actual and specified values was
too large.

If boost pressure is exceeded:
- Check Charge Air Pressure Sensor -G31-. Testing and Inspection
- Check wastegate bypass regulator valve -N75-. (Throughput in hose from turbocharger via valve to vacuum diaphragm with connector disconnected). Wastegate Bypass Regulator Valve, Checking
- Check for proper seating of vacuum diaphragm for wastegate bypass regulator valve at turbocharger.
- Check vacuum diaphragm. Vacuum Diaphragm For Wastegate Bypass Regulator Valve, Checking
- Check bearing for shaft of wastegate bypass regulator valve in turbocharger for ease of movement. If rusted solid, replace turbocharger.
- Erase DTC memory of Engine Control Module (ECM). Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If boost pressure is not reached:
- Check Charge Air Pressure Sensor -G31-. Testing and Inspection
- Check Wastegate Bypass Regulator Valve -N75-. Wastegate Bypass Regulator Valve, Checking
- Check bearing for shaft of wastegate bypass regulator valve in turbocharger for ease of movement. If rusted solid, replace turbocharger.
- Erase DTC memory of Engine Control Module (ECM). Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes