Turbocharger Recirculating Valve, Checking
Turbocharger Recirculating Valve, Checking
Special tools, testers and auxiliary items required
• Multimeter.
• Wiring diagram.
Test requirements
• Fuse (SB12) OK.
• The Engine Component Power Supply Relay (J757) 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.
• Voltage for the Turbocharger Recirculating Valve (N249) is supplied by the Engine Component Power Supply Relay (J757).
Test procedure
- Perform a preliminary check to verify the customers complaint. Refer to => [ Preliminary Check ] Preliminary Check.
Start diagnosis
- 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: 10 to 20 ohms (at approx. 20° 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).
- Operate the starter briefly.
Specified value: battery voltage.
- Switch the ignition off.
If the specified value was not obtained:
- Check the wiring from the Turbocharger Recirculating Valve (N249) electrical harness connector terminal 1 to the Engine Component Power Supply Relay (J757) socket 2/87 for a open circuit or a short circuit to 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). Refer to => [ Engine Control Module ] Engine Control Module.
- 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.
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 Turbocharger Recirculating Valve (N249).
- Erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.
- Perform a road test to verify repair.
If the DTC does not return:
Repair complete, Generate readiness code. Refer to => [ Readiness Code ] Readiness Code.
- End diagnosis.
If the DTC does return and no malfunction is detected in the wiring and the voltage supply was OK:
- Replace the Motronic Engine Control Module (ECM) (J220). Refer to => [ Engine Control Module ] Engine Control Module.
After the repair work, the following work steps must be performed in the following sequence:
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 ] Diagnostic Mode 03 - Read DTC Memory.
2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.
3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Readiness Code.