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 Motronic Engine Control Module (ECM) J220 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.

Procedure
- 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 degrees 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).

Wastegate Bypass Regulator Measure to
Valve N75 electrical harness
connector terminal
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.

If the manufacturers test box is not being used. Perform the following step.
- Remove the Motronic Engine Control Module (ECM) J220.







- 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 T60 terminal 4 for an open circuit.

Turbocharger Recirculating Motronic Engine Control Module
Valve N249 electrical harness (ECM) J220 electrical connector
connector terminal T60 terminal or test box socket
2 4

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, 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:
- Replace the Motronic Engine Control Module (ECM) J220.
- Install the engine cover with air filter.

Final procedure
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 of diagnosis.