Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Vacuum Diaphragm For Boost Pressure Regulator Valve, Checking



Vacuum Diaphragm For Boost Pressure Regulator Valve, Checking

Test conditions
- Engine oil temperature at least 80 degrees C
- no leaks on intake or exhaust side

Test Sequence







- Disconnect connector -2- at Wastegate Bypass Regulator Valve N75 -1-.







- Start engine and increase speed to maximum RPM by depressing accelerator pedal suddenly.
- Actuator rod -2- for boost pressure regulator valve must move.

If actuator rod does not move:
- Check lever for boost pressure regulator valve -1- for ease of movement. If rusted in place, replace turbocharger.

If actuator rod does not move through light prying:
- Check Wastegate Bypass Regulator Valve N75 (throughput in hose from turbocharger via valve to vacuum diaphragm with connector disconnected).

If Wastegate Bypass Regulator Valve N75 is OK:
- Replace turbocharger.