Overboost Switch: Testing and Inspection

NOTE: While trouble shooting, always check the wiring, fuses and connectors for good condition and routing. Also check ground locations for good connection. Use the wiring diagrams found in SCHEMATIC DIAGRAMS to supplement your testing efforts.





1. Connect VOLVO pressure tester/gauge #5230 or equivalent to hose at intake manifold.

Checking Switch In Engine Compartment:

Checking Switch Under Dash Above Brake Pedal:

2. Pressure switch is located next to coolant expansion tank or under dash above brake pedal.
3. Disconnect connector from sensor.
4. Connect a buzzer.
5. Increase pressure with pump. Switch should open (stop buzzing) at:

A pressure of: approx. 85 - 95 kPa (12.1 - 13.5 psi)

6. If switch does not open as specified, replace and retest with new turbo over-boost pressure switch.
7. Disconnect the test equipment and reconnect hose to intake manifold.