Wastegate Bypass Regulator Valve N75 , checking

Special tools, testers and auxiliary items required 

• Multimeter.
• Wiring diagram.

Test requirements 

• The Motronic Engine Control Module (ECM) J220 fuses OK.
• The Fuel Pump (FP) Relay J17 OK.
• Battery voltage at least 12.5 volts.
• All electrical consumers such as, lights and rear window defroster, switched off.

• On vehicles with automatic transmission, selector lever in position "P" or "N".
• A/C switched off.
• Ground (GND) connections between engine/transmission/chassis OK.
• Ignition switched off.

Test procedure 

• Perform a preliminary check to verify the customers complaint. Refer to → Motronic Engine Control Module (ECM) J220 , replacing 

Start diagnosis 

• Remove the engine cover with air filter. Refer to 24 MULTIPORT FUEL INJECTION (MFI) for Engine Code AWD and 24 MULTIPORT FUEL INJECTION (MFI) for Engine Codes AWP and AWW .

Checking internal resistance 

• Disconnect the Wastegate Bypass Regulator Valve N75 electrical harness connector - 2  -.

• Using a multimeter , check the Wastegate Bypass Regulator Valve N75 terminals 1 to 2 for resistance.

Specified value: 25 to 35 Ω (at approx. 20 ° C)

If the specification was not obtained:

• Replace the Wastegate Bypass Regulator Valve N75 Refer to 21 - TURBOCHARGER, G-CHARGER .

If the specification is obtained:

Checking Voltage supply 

• Using a multimeter , check the Wastegate Bypass Regulator Valve N75 electrical harness connector terminal 1 to Ground (GND).

Wastegate Bypass Regulator Valve N75 electrical harness connector terminal	Measure to
1	Engine Ground (GND)

• Operate the starter briefly.

Specified value: battery voltage.

• Switch the ignition off.

If the specification was not obtained:

• Check the wiring for a short circuit to Battery positive (+) or an open circuit.
• Check the electrical harness connector for damage, corrosion, lose or broken terminals.
• If necessary, repair the wiring connection.

If no malfunction is found in the wiring:

If the manufacturers test box is being used. Perform the following step.

• Install the test box Test Box 105 Pin VAG1598/31. Refer to 24 MULTIPORT FUEL INJECTION (MFI) for Engine Code AWD and 24 MULTIPORT FUEL INJECTION (MFI) for Engine Codes AWP and AWW .

If the manufacturers test box is not being used. Perform the following step.

• Remove the Motronic Engine Control Module (ECM) J220. Refer to → Motronic Engine Control Module (ECM) J220 , replacing  .

• Using a multimeter , check the Wastegate Bypass Regulator Valve N75 electrical harness connector terminal 2 to the Motronic Engine Control Module (ECM) J220 electrical harness connector T121 terminal 104 for an open circuit.

Wastegate Bypass Regulator Valve N75 electrical harness connector terminal	Motronic Engine Control Module (ECM) J220 electrical harness connector T121 terminal or test box socket
2	104

Specified value: 1.5 Ω max.

If the specification is not obtained:

• Check the wiring for a short circuit to each other, Battery (+), and Ground (GND).
• Check the electrical harness connector for damage, corrosion, lose or broken terminals.
• If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring and if the voltage supply was OK:

• Erase the DTC memory. Refer to → Diagnostic Mode 04: Reset/delete diagnostic data 
• Perform a road test to verify repair.

If the DTC does not return:

Repair complete, Generate readiness code. Refer to →Readiness Code  .

• End diagnosis.

If the DTC does return and no malfunction is detected in the wiring and the voltage supply was OK:

• Replace the MFI Engine Control Module (ECM) J220. Refer to → Motronic Engine Control Module (ECM) J220 , replacing  .
• Assembly is performed in the reverse of the removal.

Final procedures 

After the repair work, the following work steps must be performed in the following sequence:

1. Check the DTC memory.
2. If necessary, erase the DTC memory.
3. If the DTC memory was erased, generate readiness code.

End diagnosis