Air Bypass Valve Solenoid: Testing and Inspection

Turbocharger Recirculating Valve N249, 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 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: 20 to 30 Ohms (at approx. 20 degrees C)

If the specification was not obtained:
- Replace the Turbocharger Recirculating Valve N249.

If the specification was obtained:

Checking Voltage supply







- Using a multimeter , check the Turbocharger Recirculating Valve N249 electrical harness connector terminal 1 to Ground (GND).

Turbocharger Recirculating Measure to
Valve N249 electrical harness
connector terminal
1 Engine Ground (GND)

- Operate the starter briefly.

Specified value: battery voltage.

- Switch the ignition off.

If the specified value was 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 wiring connection.

If no malfunctions are 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 Motronic Engine Control Module (ECM) J220.







- Using a multimeter , check the Turbocharger Recirculating Valve N249 electrical harness connector terminal 2 to Motronic Engine Control Module (ECM) J220 electrical harness connector T60 terminal 21 for an open circuit.

Turbocharger Recirculating Motronic Engine Control Module
Valve N249 electrical (ECM) J220 electrical connector
harness connector terminal T60 terminal or test box socket
2 21

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 procedures
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.