Turbocharger Recirculating 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 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 

-- Lift the vehicle on a hoist to access the turbocharger recirculating valve connector.

Checking internal resistance

-- Disconnect the Turbocharger Recirculating Valve -N249- electrical harness connector -2-.

-- Using a multimeter, check the Turbocharger Recirculating Valve -N249- terminals 1 to 2 for resistance.

Specified value: 13.6 Ω +/- 5 ohms 

If the specified value was Not obtained: 

-- Replace the Turbocharger Recirculating Valve -N249- Refer to the appropriate Service Information.

If the specified value was obtained: 

Checking Voltage supply

-- Using a multimeter, check the Turbocharger Recirculating Valve -N249- electrical harness connector terminal 1 to engine ground.

-- Start the engine.

Specified value: Battery voltage. 

-- Switch the ignition OFF.

If the specified value was Not obtained: 

-- Check the wiring for an open, short circuit to each other, high resistance or short to ground.

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

-- If necessary, repair the wiring connection.

If the specified value was obtained: 

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 Motronic Engine Control Module (ECM) -J623-. Refer to the appropriate Service Information.

-- Using a multimeter, check the Turbocharger Recirculating Valve -N249- electrical harness connector terminal 2 to Motronic Engine Control Module (ECM) -J623- electrical harness connector T60 terminal 50 for an open circuit.

Turbocharger Recirculating Valve -N249- electrical harness connector terminal	Motronic Engine Control Module (ECM) -J623- electrical connector T60 terminal or test box socket
2	50

Specified value: 1.5 Ω max. 

If the specified value was Not obtained: 

-- Check the wiring for an open or high resistance.

-- 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 .