WASTEGATE Bypass Regulator Valve, Checking

Special Tools And Workshop Equipment Required 

• Multimeter
• Wiring diagram

Test requirements 

• The Motronic Engine Control Module (ECM) - J623- 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 PRELIMINARY CHECK 

Start diagnosis 

-- Remove the engine cover with air filter. Refer to the appropriate service information.

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 Ω (at room temp.)

If the specification was not obtained:

-- Replace the Wastegate Bypass Regulator Valve -N75-. Refer to the appropriate service information.

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 engine 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.

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

-- Remove the Motronic Engine Control Module (ECM) -J623-. Refer to the appropriate service information.

-- Using a multimeter, check the Wastegate Bypass Regulator Valve -N75- electrical harness connector terminal 2 to the Motronic Engine Control Module (ECM) -J623- electrical harness connector T60 terminal 51 for an open circuit.

Wastegate Bypass Regulator Valve -N75- electrical harness connector terminal	Motronic Engine Control Module (ECM) -J623- electrical connector T60 terminal or test box socket
1	fuse SB 7
2	51

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, 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 Motronic Engine Control Module (ECM) -J623-. Refer to the appropriate service information.

-- Install the engine cover with air filter. Refer to the appropriate service information.

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 .
2. If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
3. If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .