Wastegate Bypass Regulator Valve (N75), Checking

Wastegate Bypass Regulator Valve (N75), checking

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• The Fuse (SB12) OK.

• The Motronic Engine Control Module (ECM) Power Supply Relay (J271) 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.

• Voltage for the Wastegate Bypass Regulator Valve (N75) is supplied by the Motronic Engine Control Module (ECM) Power Supply Relay (J271).

Test procedure

- Perform a preliminary check to verify the customers complaint. Refer to => [ Engine Control Module (ECM) (J623), replacing ] Engine Control Module (ECM) (J623).

Start diagnosis

- Remove the engine cover with air filter.

Checking internal resistance

- Disconnect the Wastegate Bypass Regulator Valve (N75) electrical harness connector- 1 -.





- Using a multimeter, check the Wastegate Bypass Regulator Valve (N75) 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 was 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:

Checking wiring

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

- Install the test box.

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

- Remove the Engine Control Module (ECM) (J623). Refer to => [ Engine Control Module (ECM) (J623), replacing ] Engine Control Module (ECM) (J623).

- Using a multimeter, check the Wastegate Bypass Regulator Valve (N75) electrical harness connector terminal 2 to the Engine Control Module (ECM) (J623) electrical harness connector T60 terminal 4 for resistance.










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.

- Erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.

- Perform a road test to verify repair.

If the DTC does not return:

Repair complete, Generate readiness code. Refer to => [ Readiness Code ] Engine.

- End diagnosis.

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

- Replace the Engine Control Module (ECM) (J623). Refer to => [ Engine Control Module (ECM) (J623), replacing ] Engine Control Module (ECM) (J623).

- 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. 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 ] Engine.

End of diagnosis