Wastegate Bypass Regulator Valve, Checking

Wastegate Bypass Regulator Valve, Checking

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• The Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) (J248) fuses 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 => [ General Diagnosis ] General Diagnosis.

Start diagnosis

- Disconnect the Wastegate Bypass Regulator Valve (N75) electrical harness connector.

Checking internal resistance

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





Specified value: 20 to 30 ohms (at approx. 20° C)

If the specification was not obtained:

- Replace the Wastegate Bypass Regulator Valve (N75).

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).









- 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, loose 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. Refer to => [ 68-Pin Test Box Adapter, VAG1598/19, Installing ] Diesel Direct Fuel Injection ECM, Checking.

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

- Remove the Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) (J248). Refer to => [ Diesel Direct Fuel Injection ECM, Replacing ] Diesel Direct Fuel Injection ECM, Checking.

- Using a multimeter, check the Wastegate Bypass Regulator Valve (N75) electrical harness connector terminal 2 to the Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) (J248) electrical harness connector T60 terminal 29 for an open circuit.









Specified value: 1.5 ohms 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, loose 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:

- Replace the Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) (J248). Refer to => [ Diesel Direct Fuel Injection ECM, Replacing ] Diesel Direct Fuel Injection ECM, Checking.

Final procedures

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

1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Mode 03 - Read DTC Memory.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.

3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Readiness Code.