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.
  Fig 1: Identifying Fuses On E-Box In Engine Compartment, Left Side

  Courtesy of AUDI OF AMERICA, LLC
• 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 specified value was not obtained:

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

-- Go to Final procedures

If the specified value was 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)

-- Turn the ignition switch ON.

Specified value: battery voltage.

-- Switch the ignition off.

If the specified value was not obtained:

-- Check for an open or grounded circuit between terminal 1 and fuse SB24.

-- Check the wiring connection for damage, corrosion, loose or broken terminals.

-- If necessary, repair the faulty wiring connection.

-- Repair the circuit and replace any open fuses.

-- Go to Final procedures

If the specified value was obtained:

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
2	51

Specified value: 1.5 Ω max.

If the specified value was not obtained:

-- Check the wiring connection for an open circuit, short circuit to Battery voltage or Ground

-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.

-- If necessary, repair the faulty wiring connection.

-- Go to Final procedures

If the specified value was obtained:

-- With the Motronic Engine Control Module (ECM) Connectors still unplugged - J623 -. Refer to appropriate service information.

-- Use a Multimeter, Check the Wastegate Bypass Regulator Valve - N75- electrical harness connector terminal 2 to engine ground for continuity

- If Specified value is 1.5 Ω or less

-- Check the wiring connection for a short circuit to Engine Ground

-- If necessary, repair the faulty wiring or connection, If no faults were found Replace the Motronic Engine Control Module (ECM) - J623 -. Refer to appropriate service information.

Final procedures 

-- Reinstall the engine cover with air filter, if necessary. Refer to the appropriate service information.

-- 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 .